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CWIHP Working Paper #78
March 2016

China’s False Allegations of the Use of Biological Weapons by the United States during the Korean War

Milton Leitenberg



On the early morning of June 25, 1950, North Korean military units, using Soviet supplied tanks and heavy artillery, invaded South Korea all along the 38th parallel.

Kim Il Sung, North Korea’s leader, had been asking Stalin for permission to invade the South since March 1949, but his initial proposals were turned down. After the Chinese Communists achieved victory in October 1949, a second appeal by Kim in April 1950 was approved. In the months leading up to June 1950, Soviet supply trains full of arms and munitions began to flow to North Korea, while divisions composed of ethnic Koreans who had fought with Mao Zedong’s forces in China were transferred to North Korea’s armies. At the same time, senior Soviet military officers devised the North Korean invasion plan and trained North Korea’s armies.

After June 25, the United States and United Nations forces entered the war on behalf of the south; Chinese armies and the Soviet Air Force fought on behalf of the north. The war lasted until July 1953, and ended only with an armistice, not a peace treaty. Both Koreas—north and south—were totally devastated, and as many as 4.5 million people died during the war. The Korean Peninsula remains destabilized to the present day. With North Korea’s development of nuclear weapons and intermediate range ballistic missiles since 2009, it promises to remain so for the foreseeable future.

A little remembered aspect of the Korean War is an issue of great importance to those concerned with arms control and allegations of the use of Weapons of Mass Destruction (WMD), namely nuclear, biological, and chemical weapons. During and after the war, North Korea, China, and the Soviet Union alleged that the United States used biological weapons (BW) on an enormous scale in areas of both China and North Korea. Despite the public disclosure of Soviet Central Committee documents in 1998—eighteen years ago—which revealed that the allegations were fraudulent, China and, much more noisily, North Korea still maintain the charges.[1]

The purpose of this Working Paper is to describe recent publications in Chinese journals of an unprecedented nature on the subject. A memoir by Wu Zhili, Director of the Chinese People’s Volunteer Army Health Division during the Korean War, describes the allegations as a “false alarm” and reveals that there was no use of biological weapons by the Americans in the war. Although he does not go as far as to admit that the allegations were really active fraud and disinformation, much of his narrative makes that evident. Two other publications by Qu Aiguo, a Senior Colonel affiliated with the PLA Academy of Military Science History, evaluate, for the first time, the Soviet documents released in 1998. Qu moves away from the standard-line that “the US used BW against China and North Korea” and concludes that “we cannot deny that that the Americans used BW.” Although only a change of a few words, it is a significant shift in the Chinese presentation of the issue.  Nevertheless, it remains dishonest.

In addition to discussing these new Chinese writings about the BW allegations, the Working Paper reproduces a number of newly declassified documents which demonstrate the extent of communications between Mao, Stalin, and Zhou Enlai, as well as two documents which authenticate the 1998 Soviet documents which disproved the allegations. Based on what we know about the US BW program in 1952 as well as the proof contained in the Soviet Central Committee documents released in 1998, the Working Paper concludes that the Korean War BW allegations against the US, an accusation of the use of a weapon of mass destruction, were false, a grand piece of political theater.

A Chronology of BW Allegations

The grounds for these charges were laid two years before the Korean War began. In 1949 and 1950, Soviet propaganda charged that the US was testing biological weapons (plague) against the native Inuit peoples of Alaska. In Soviet reporting of the 1949 Khabarovsk’s trials for members of Japan’s World War II-era BW program, Pravda stated that the United States was “preparing for new crimes against humanity” (i.e., biological warfare). Chinese broadcasts amplified these claims, reporting that the US government was collaborating with Lt. General Shiro Ishii, one of the major figures responsible for the Japanese biological weapons program in China during World War II, ostensibly in preparation for subsequent use of biological weapons by the US against China. In the late spring and early summer of 1950, just before the start of the Korean War, East Germany, Czechoslovakia, and Poland also began a campaign of allegations that the US was dropping Colorado beetles over their fields to destroy their potato crops. Finally, on January 21, 1951, Pytr Pospelov, Director of the USSR’s Marx-Engels-Lenin Institute and a member of the Soviet Central Committee, promulgated a “hate America campaign” in a speech to the full Soviet Politburo. Pospelov claimed that “the hands of the American imperialists are steeped in the blood of the Russian people.”

The actual allegations of BW use during the Korean War began on May 8, 1951. North Korea’s Foreign Minister, Pak Heon-yeong (Pak Hon-yong), claimed that the United States had used biological weapons between December 1950 and January 1951, and was spreading smallpox in North Korea. Chinese statements also charging the use of BW by the United States were made on March 14, May 19, 24 and 25, and a final one for 1951 on June 22. The Chinese government also charged that the US used chemical weapons in the Korean War on ten occasions between March 5 and May 13, 1951. North Korean statements continued into July, before stopping for the remainder of 1951.[2]

The major campaign alleging US BW use began on February 22, 1952, and was of quite a different character than the earlier claims described above. On that day, the North Korean Foreign Minister again issued an official statement addressed to the United Nations Secretariat, charging that in January and February the US had made multiple air drops over North Korea, littering the earth with insects infected with the microorganisms that caused plague, cholera, and other diseases. On the very same day, February 22, the front page of China’s major newspaper, Renmin ribao (People’s Daily), carried a story repeating the North Korean charges, accompanied by photographs of objects allegedly dropped by US aircraft and microscope slides of bacteria. Two days later, on February 24, China’s Foreign Minister, Zhou Enlai, supported the North Korean charges in a public statement, and on March 8, Zhou expanded the charges to claim that, between February 29 and March 5, the US had sent 448 aircraft on no fewer than 68 occasions to drop germ-carrying insects over Northeast China. From there the charges exploded for months to come, with Chinese news agencies reporting many thousands of US aircraft sorties dropping biological agents over China. The alleged pathogens also included the causes of animal diseases, as well as four different plant diseases. China claimed that 955 sorties by 175 groups of US aircraft flew over Northeast China, dropping BW between the dates of February 29 and March 31, 1952. China also claimed that US aircraft spread BW over “70 cities and counties of North Korea…on 804 occasions, according to incomplete reports.” Nevertheless, on no occasion did the Chinese or North Koreans claim to have shot down a US aircraft carrying biological weapons or the delivery systems for them.

Communist Investigations of the Allegations

Soviet representatives in the United Nations took up the charges of BW use on behalf of the Chinese and North Koreans. In addition to raising the issue at international forums, between mid-March and mid-April 1952, one-quarter of Soviet media coverage was devoted to the BW allegations against the US. Mass public demonstrations of protest were held all over the USSR and its Eastern European satellites, as well as in virtually all Western European capitals. In total, millions of people marched in condemnation of the alleged US use of BW.[3]

The Chinese and North Koreans rejected repeated offers of on-site investigations by the World Health Organization and the International Committee of the Red Cross on various dubious and propagandistic pretexts. Instead, the two governments hosted their own “investigations” carried out by Soviet proxy organizations. The first was carried out by a team sent by the International Association of Democratic Lawyers, a group belonging to the World Peace Council, an organization subordinated to a department of the Soviet Central Committee. It visited North Korea from March 5-19, 1952, within days after the 1952 allegations began. The group released two reports in Beijing on March 31 and April 2, 1952. These repeated the North Korean and Chinese charges verbatim, describing the alleged BW “as an act of genocide and a particularly odious crime against humanity.”[4] The Chinese government also established its own investigating body, the Commission of the Medical Headquarters of the Korean People’s Army on the Use of Bacteriological Weapons, which reportedly began its work in the very first days of March 1952.[5] This extensively staffed organization gathered the evidence for the more significant “International Scientific Commission for the Investigation of the Facts Concerning Bacterial Warfare in Korea and China,” again organized by the Soviet proxy World Peace Council. It is commonly referred to as the ISC, or “the Needham Commission,” as it was chaired by the eminent British scientist, Marxist, and sinophile, Dr. Joseph Needham. The most instrumental member of the ten members of the ISC was Dr. Nikolay Zhukov-Verezhnikov, a Soviet microbiologist and also a KGB general. He was in fact the only bacteriologist in the group, but the role that he played was significant for reasons other than his professional training. He had served as the chief medical expert for the Soviet trial in Khabarovsk of the Japanese BW scientists. This provided him with information about the air-dropped devices and materials that Japan had used to disperse BW agents in China. The ISC report alleged that the US used the same or very similar mechanisms.

The ISC was present in China and North Korea between June 25 and August 31, 1952, and their massive 669-page report was published in Beijing in 1952.[6] The ISC report documents fewer incidents and fewer types of incidents than were reported by the lawyers’ group, which in turn were fewer than reported by Chinese media sources. The most significant aspect of both the jurists’ and ISC “investigations” is that neither group did any field investigating of their own. They were presented with “evidence” by the Chinese and North Koreans, which they accepted, on faith, as fact. They attempted to corroborate nothing, and Needham, the group’s chair, plainly acknowledged this in press interviews following the release of the ISC report.

Rejecting the Allegations

The charges were immediately and repeatedly denied by US delegates at the UN, by US Secretary of State Dean Acheson, and by the senior US military commanders in Korea. The ISC report was also strongly criticized by individual bacteriologists, entomologists, epidemiologists, and virologists in the UK, US, and Australia for pairing types of insects with pathogens that were not carried naturally by such insects; for claiming the use of insect vectors in seasons when such insects would not be present and would freeze in moments after exposure to sub-zero freezing conditions; and on other technical grounds.[7]

In subsequent years, other criticisms and admissions were even more telling. Tibor Meray, a Hungarian journalist who had spent the Korean War inside North Korea, reported that North Korean peasants told doctors at a Hungarian field hospital that paper packets of insects had been placed in the snow by Chinese soldiers. The North Korean Deputy Minister of Health also told Meray that North Korea had been informed of germ attacks by “reports from Chinese Volunteers.”[8] Meray also reported that during party-to-party discussions in Beijing between Chinese officials and those of Poland and Yugoslavia in 1956, the Chinese participants stated that “they considered the whole Korean War to have been a mistake into which they had been pushed by Stalin. And that they believed the accusations about germ warfare to have been without foundation.[9] In the 1990s, one of the Chinese cease-fire negotiators in 1953 told an historian in reference to the BW allegations, that “it was all bullshit.”[10]

American BW Policy

In the years since the Korean War, a “pro- and con” literature has appeared regarding the BW allegations. Those that supported the old Chinese and North Korean charges were without exception of pronounced left-wing political persuasion of one kind or another. More than a dozen different analysts who did not believe the accusations against the US tried to deduce why the Chinese, North Koreans, and Soviets had made the false allegations, and what benefits they sought from them. There were nearly as many postulated reasons as there were authors.[11] Within the US government, such analyses began almost immediately after the charges were made: the first Special National Intelligence Estimate on the subject was produced as early as March 25, 1952.[12]

As regards US BW policies and capabilities at the time of the Korean War, policy on BW had been promulgated in NSC-62 on February 1, 1950, months before the war began. It states that “chemical, biological and radiological weapons will not be used by the United States except in retaliation.”[13] This policy remained in force throughout the Korean War and was confirmed, word for word, in NSC-147, on April 2, 1953, which stated that it “appl[ied] to UN operations, 1952-1953.”[14] These US national policy determinations were, however, not publicly disclosed. US policy was not changed until March 15, 1956, when NSC-5062/1 permitted first use of chemical or biological weapons by US military forces, but only with presidential approval.

There is considerable American evidence that there was no violation of these NSC policies during the Korean War, including President Harry Truman’s reply to a letter by Congressman Robert Kastenmeier dated July 25, 1969 in which he wrote, “I wish to state categorically that I did not amend any Presidential order in force regarding biological weapons nor did I at any time give my approval to its use.”[15] Supporting this conclusion is an affidavit that Brigadier General H. Hillyard, Secretary to the Joint Chiefs of Staff, provided as evidence during a US court trial in April 1959, stating that “after a diligent search no record or entry has been found to exist in the records of the Joint Chiefs of Staff which discloses that the President or any authority superior to the Secretary of Defense, acting at the discretion of the President, did therein at any time, either expressly or impliedly, authorize, consent to, or permit any Armed Force, or any element thereof, to use or employ any form of toxic chemical warfare or biological warfare during the period stated above.”[16]

During World War II, the US BW program was engaged solely in research, and it had produced no stockpile of BW agents. After 1945, the United States neither produced nor procured any biological munitions until the end of 1951. That first agent was wheat rust, an anti-plant agent meant for use against the wheat crops of the USSR.[17] It cannot produce any human disease, and neither China nor North Korea ever alleged that the US had dispersed this agent. The second BW agent that the US produced was a human pathogen, but it was not ready until the end of 1954, about 16 months after the Korean War was over. It was for the organism Brucella suis, which produces the incapacitating disease Brucellosis. [18] Brucellosis was not one of the diseases that China or North Korea ever charged the US with spreading.

Thus the only BW agent that the US possessed during the Korean War was for selective use against Soviet food grain crops, and the Chinese and North Koreans never alleged that it had been used. When the first US anti-personnel BW agent became available, the Korean War was already over and the US was never accused of having dispersed this pathogen over China or North Korea.

Declassified Soviet-Era Documents

In January 1998, twelve Soviet-era documents were obtained through an intermediary from the Archive of the CPSU Central Committee (now presumably housed at the Russian State Archive of Socio-Political History [RGASPI], or the Russian State Archive of Contemporary History [RGANI]). One of the files, dated February 21, 1952—one day before the North Korean Foreign Minister’s public statement on February 22, 1952—was from Mao to Stalin, reporting that the US has used BW, “delivered by aircraft and artillery.”[19] (As indicated below, the version obtained in 1998 of that particular document was only a fragment, and the full document was published by a Russian archive in 2010.) The remaining eleven documents released in 1998 all date from between April 13 and June 2, 1953, the months immediately following the death of Stalin. They include four types of documents: messages from the CPSU Central Committee to Mao or Kim Il Sung; messages to the Soviet Ambassador or senior military officers in Beijing or Pyongyang; replies from them reporting on their conversations with Mao or Kim; or internal memoranda within the CPSU Central Committee. Although the provenance of the documents was initially contested, in 1990 three former Soviet military and civilian officials in Moscow confirmed the authenticity of the files.

The 1953 documents originated within the CPSU Central Committee as a part of the post-Stalin struggle for leadership between Beria and Khrushchev. That battle took place through an ostensible dispute over three policy issues: the Moscow “Doctors Plot,” which was to have initiated a new purge directed at Stalin’s closest subordinates, Beria’s ideas concerning East Germany and the potential for a European agreement on the unification of the two divided parts of Germany, and the Korean War BW allegations. The first and third of these subjects were fought over by attacks on officials who were protégés of either Beria or Khrushchev. As Beria initiated the process that led to the Korean War BW documents, this was apparently a means by which he attacked Khrushchev, as was the renunciation of the Doctors Plot.

One of the most important documents in the collection—dated May 2, 1953, a Resolution of the Presidium of the USSR Council of Ministers, addressed to Mao, brusquely states:                       

The Soviet government and the Central Committee of the CPSU were misled. The spread in the press of information about the use by the Americans of bacteriological weapons in Korea was based on false information. The accusations against the Americans were fictitious…

Soviet workers responsible for participation in the fabrication of the so-called “proof” of the use of bacteriological weapons will receive severe punishment.[20]

The other documents detailed exactly how Soviet military personnel serving with the Soviet military mission in North Korea assisted in that fabrication of “evidence.” One file, for example, is a telegram from the Soviet ambassador in Beijing to Soviet Foreign Minister Molotov reporting on his conversations with Mao Zedong and Zhou Enlai on May 12, 1953, during which Mao (falsely) blamed the allegations on reports from Chinese frontline commanders in North Korea.[21] One telegram from Lt. General Razuvayev, the Soviet ambassador to the DPRK and Chief Soviet Military Advisor to the KPA, reported on his discussions held with Pak Jang-ok (Pak Chang-ok), Secretary of the DPRK Central Committee, who:

expressed great surprise at the actions and positions of V.N. Razuvayev…We were convinced that everything was known in Moscow. We thought that setting off this campaign would give great assistance to the cause of the struggle against American imperialism. In his turn, Pak Chang-ok did not exclude the possibility that the bombs and containers were thrown from Chinese planes, and [that] there were no infections.[22]

These Soviet Central Committee documents provided incontrovertible evidence that the Korean War BW allegations made against the United States were contrived and fraudulent.

A Chinese Admission from Wu Zhili

Despite America’s public denials, the United States’ in ability in 1952 to deliver the claimed bacteriological agents, and the Soviet documentation made available in 1998, Chinese and North Korean official sources still maintain the old allegations and repeat them in books and statements and through the publications of proxy groups.[23] However there is now, finally, an enormously significant posthumous publication from a former senior Chinese military officer who was critically involved in the Korean War BW allegations: Wu Zhili, Director of the Chinese People’s Volunteer Army Health Division during the Korean War. He wrote a brief memoir in September 1997, and it was found among his papers after he died in 2008. It was published in a Chinese journal only in November 2013, and an English language translation, arranged by this author, first became available in April 2015.[24] Wu Zhili’s own testimonial contains a second one as well, by Huang Kecheng, Chief of Staff of the Chinese Army during the Korean War and later secretary general of the Central Military Commission. Wu Zhili’s testimonial overturns everything previously presented in Chinese sources (and even what has been published up to the present day). His opening lines are:

It has already been 44 years [in 1997] since the armistice of the Korean War, but as for the worldwide sensation of 1952: how indisputable is the bacteriological war of the American imperialists?

The case is one of false alarm.

Wu begins his narrative on January 29, 1952. There is no mention of the North Korean and Chinese allegations of 1951. On that day in 1952, a telegram arrived from one of the Chinese divisions in North Korea reporting that some 80 insects, ticks, and fleas had been found in the snow among the Chinese trenches. A telegram reporting the same information was sent later that day to CPV Commander Peng Dehuai, to the Party Central Committee, and to “every unit to alert them and require timely reports of any similar situations.” However, Wu’s laboratory was unable to isolate any pathogenic bacteria on these insects and ticks. In addition, Wu and his assistants could “not discover people who had died suddenly or suspiciously fallen ill.” Wu also considered the facts that severe winter was not the time to carry out BW; that US military trenches were “not more than ten meters away” from Chinese and North Korean ones;” that Korea “already had an epidemic of lice-borne contagious diseases;” and that every North Korean house contained fleas. He came to the conclusion that one could not prove that the US was carrying out BW. One of his colleagues agreed, saying “I think it is a false alarm.” Paradoxically, at that same moment, a telegram arrived from the CCP Central Committee stating that “the enemy had not carried out biological warfare, but that we could still take advantage of this to reinforce health work.”

Wu reported his views to one of the deputy commanders of the Chinese forces. He was advised to inform Peng Dehuai. He dispatched a telegram to Peng, who then requested him to come to headquarters. Wu’s North Korean counterpart, the Chief of the Korean People’s Army Disease Prevention Bureau, had also been unable to produce evidence of BW, and he accompanied Wu to Peng’s headquarters. Wu briefed Peng and twelve members of his staff. Peng’s response was shocking, and an ostensible death sentence: “Our Health Director is an American imperialist operative and speaks on behalf of the enemy.” Wu’s North Korean colleague told him afterwards that he thought Wu would be beheaded. However, after an intermission to consult with his staff, Peng returned to say that Wu should keep his job, and that one of Peng’s deputy commanders would be his superior officer. “Do a proper job. Set up a general disease prevention office and be the Deputy Director.” The same night Wu received a telephone call from the Soviet Chief of Staff at Peng’s headquarters with a question:  “Stalin has asked whether bacteriological warfare is really occurring.” Wu replied “Go ask Commander Peng.” It is not clear if Stalin’s phone call was before or after Mao’s cable to Stalin on February, 21, but it would appear to have been before that date.

The remaining portions of Wu’s memoir are divided amongst explanations of his work to protect the health of the Chinese military forces in North Korea and the tasks carried out to make it appear that the US was using biological weapons. One of those tasks involved hosting the three visiting Commissions: China’s own, the Jurists, and Needham’s ISC. Regarding the ISC, Wu remarked that “although they believed that the American imperialists conducted biological warfare, we could not produce proof of the issue. Soviet Academician Zhukov was entrusted [with the task] by Stalin.” That is, Zhukov-Verezhnikov would produce the “proof” that Wu’s field investigations could not provide. The ISC returned to Beijing and presented their report to Mao. According to Wu, Mao replied, “I see that the American imperialists are experimentally engaged in bacteriological warfare.”[25] Wu euphemistically remarks of the government’s own Chinese Commission that “of course it fully cooperated” with the fraud. The Chinese Commission was co-headed by Li Dequan, the First Minister of Health of the PRC in 1949 and the President of the Chinese Red Cross in 1950. Perhaps what Stalin was really asking in his phone call was whether the Americans were doing anything in addition to what Soviet personnel in North Korea were doing to assist the fraud.

In contrast to all three Commission reports, Wu’s own staff could find no bacteria and no sick people due to BW in all of 1952. Only Salmonella-type organisms were discovered; no cholera, no plague. One Chinese army lieutenant refused to lie to the ISC about where he had found fleas, telling Wu: “Chairman Mao taught him not to lie. He was unable to move. What to do? Only to persuade him to submit to the current needs of the struggle against the enemy…As for the plague, that was easy, we [could] cause it to appear.” However, it required a trip of five days in order for one of Wu’s assistants to bring back two tubes of plague cultures from Shenyang in Northeast China. In regard to the “confessions” by US airmen that they had dropped BW, a key part of Chinese propaganda and of the ISC report, as well as the argumentation used by subsequent defenders of the Chinese allegations. Wu commented sarcastically: “I really admire the persuasion work of our personnel in the prisoner-of-war camps.”

Wu reported personally to Zhou Enlai three times in Beijing. He reports that when the cable from the Soviet Central Committee arrived in May 1953, Premier Zhou immediately sought out Chief of Staff Huang Kecheng and Deputy Commander Hong Zuezhi and asked, “Have you been up to tricks?” Hong answered “Yes, otherwise we wouldn’t have had anything to report.” Zhou’s question is puzzling, or duplicitous: he must have known that since February 1952. Wu erroneously describes the Soviet cable as using his own phrase “false alarm,” whereas it refers to “false” and “fictitious” information. Wu then claimed that “Premier Zhou promptly ordered a retraction. Afterwards China did not raise the matter again.” That, however, is not true. An official history of the Korean War written by Chinese military historians, published by the Military Science Press in Beijing in 1988, continues to repeat the Chinese Korean War BW allegations.[26] So do two significant papers published in 2008 and 2010 (discussed below), as well as a Chinese museum exhibit in Harbin. The author of this Working Paper has no knowledge of any public Chinese “retraction” to this date.

Wu then describes a real retraction, by Huang Kecheng, former PLA Chief of Staff during the Korean War, but made only to Wu in private:

When he was sick, Huang Kecheng asked me to pass his opinion to the comrades at the Academy of Military Sciences who were editing an encyclopedia: ‘The American imperialists did not engage in bacteriological warfare in Korea. Right now the two countries’ relationship is not bad, and it would be inappropriate to keep talking about this issue.’ When they heard this, they sent someone to ask if there had been bacteriological warfare after all. I only said that we do not have enough evidence. This has been my silent regret for decades. There has been no other.  

Huang died on December 28, 1986, and so his request to Wu presumably was made some time in the middle or late 1986. Unfortunately, when the Chinese military historians came to talk to Wu, he lost his nerve and provided an ambiguous reply. Although suggestive, it was certainly not one that clearly and explicitly reinforced Huang’s recantation, which would have been a clear and simple statement that there was no US BW during the Korean War against China or Chinese military forces. Both the aforementioned Chinese military histories were published after Wu’s interaction with the military historians who came to see him. Whether the military historians would have been allowed by higher Chinese political and military authorities to write anything differently, we will never know. When Wu apologized to Huang, Huang replied, “You don’t need to feel this way; this was political struggle! Furthermore you had expressed your views on bacteriological warfare from the beginning. It was not an easy situation, and you were given responsibility too late.” Nevertheless, Wu regretted his failure for the rest of his life.

Wu wrote his memoir eleven years after his exchange with Huang, apparently only in the last years of his own life, and he never sought to publish it while still alive. Wu ends his memoir on a note of belated remorse: “I think that there will be a day in history to speak clearly about this incident. Now that I am an 83-year-old man who knows the facts and is no longer on duty, it is fitting to speak out; the bacteriological war of 1952 was a false alarm.” However although Wu put pen to paper, which was brave and highly commendable, he still hesitated to truly “speak out.” And if there was any “false alarm” at all, it can only have lasted for the week or so between January 29 and Wu’s report to Peng Dehuai. From that point on, it was active fraud and disinformation. Although Huang Kecheng did not leave the detailed record that Wu did, his wording of “the bottom line” was simpler and more straightforward: there had been no US BW during the Korean War.

New or Old Interpretation? Reading Qu Aiguo                                                 

Two additional papers of importance were published in China in 2008 and 2010. The author of both papers, Qu Aiguo, was at the time of writing a Senior Colonel affiliated with the PLA Academy of Military Science History. Although the conclusions of these papers are quite different from Wu’s, they mesh with his memoir and provide some additional surprising information.[27]

Qu begins both papers by referring specifically to the papers by Leitenberg and Weathersby which were published in the Cold War International History Project Bulletin in 1998 and provides an extremely brief rendering of their contents. To this author’s knowledge, this is the first time such information has appeared in the open in China.[28]

Qu goes on to state that “some scholars in China made a new interpretation” of the entire Korean War BW allegations and that “they believe that the decision of the CCP Central Committee is based on the false judgment from the Volunteer Army.” They further believe that “The anti-germ war is a kind of ‘political propaganda’ launched by China, North Korea, and the Soviet Union.” Qu never identifies who these “scholars in China,” are, and whether he is referring to Wu Zhili or others remains unknown. He then states that he disagrees with this “new interpretation.”

Qu also mentions that “the Soviet Union sent nine senior experts” to aid China in regard to the purported US BW. This has never before been mentioned by any source, and presumably he is not conflating the “nine senior experts” with the members of the Needham-led ISC. It is conceivable that these nine Soviet experts were the individuals that produced the fabricated “evidence” that Zhukov-Verzhnikov provided to the ISC, unless the experts on the Chinese Commission and/or Wu Zhli’s staff (or some combination of the two) did not themselves do it. This detail still remains unclarified. Qu then goes on to narrate the messages exchanged within China by Marshall Nie Rongzhen and others, information that has been available at least in part since the 1990’s and was included in the 1998 CWIHP publication.

Qu then actually paraphrases three of the Soviet Central Committee documents, amazingly even the one accusing Mao of misleading the USSR. He does not include Mao’s reply to the Soviet ambassador, but by and large he does not alter the contents of the Soviet documents that he selected to discuss. This is apparently the first publication in China that has made reference to those documents (a third “first”), though Qu then presents three arguments against the substantive content of the cables (actually five, but he combines several of them):

-- They are not original copies; which is correct. The 1998 CWIHP publication explains how they came to be copied.[29]

-- They were copied by a Japanese journalist; that is not correct. They were copied by a Russian researcher with access to the Soviet Presidential Archive, where the documents were located.[30]

-- The Russian government has never validated or published them. That was correct when Qu wrote his papers, but it was no longer correct by the end of 2010. The full text of Mao’s cable to Stalin of February 21, 1952 and Stalin’s reply of February 23, as well as three additional messages from Zhou Enlai to Stalin were published by the Russian historical archive RGASPI in 2010, the very year of Qu’s second publication. They are discussed below. But it is no great surprise that the documents had previously been unpublished or unvalidated by the Soviet or Russian governments. Czarist-era documents dating from World War I have still never been declassified and released in Russia. However, the documents which were published in the 1998 issue of the CWIHP Bulletin were independently and privately validated in 1990 by three former Soviet government officials still residing in Russia at that time, including one of the individuals involved in one of the cables.

 -- The cables were part of a political struggle, making them untrustworthy. That is correct, they were part of the political struggle between Beria and Khrushchev, but that does not invalidate them in any way. If someone in China, officially or surreptitiously, were to now release documents concerning the Lushan CCP conference in 1959, that would not make the documents unreliable because they concerned an internal struggle in the senior Chinese leadership between Mao and his closest associates.

-- The Chinese government has never confirmed the documents and they are not available in Chinese archives. Of course they have never been confirmed, but they unquestionably must exist in Chinese Central Committee archives. If a Russian historical archive can publish cables in full from Mao and Zhou Enlai to Stalin concerning the Korean War BW allegations, they certainly exist in some Chinese archive, just as the messages to and from Nie Rongzhen do.

Qu then makes two statements:

1. For the above reasons one cannot and should not trust the contents of the copied documents.

2. Therefore “We cannot deny that that the Americans used BW.” The double negative is an enormous change from all previous Chinese phrasing. Heretofore the wording in all Chinese publications without exception has been “The US used BW against China and North Korea.” Now it was an obviously convoluted phrasing, “We cannot deny that they used BW.”

What is additionally interesting is that all this information is deleted in the 2010 version of Qu’s paper, just two years after the initial paper in 2008. Since the author is a military officer and is/was a member of a PLA institute of Military History, it must be assumed that his 2008 paper would have been vetted and approved for publication by his superiors at the institute, up to and including the Institute’s Director, and presumably also a party official at the Institute.

New Soviet Documentation

As noted above, in 2010 the Russian historical archive RGASPI published six documents from Mao, Stalin and Zhou Enlai.[31] The long message from Mao to “Comrade Filippov,” Stalin’s code-name in correspondence between Mao and Stalin, is printed in full. It demonstrates that we had unfortunately only been able to obtain a small portion of that particular message in 1998. The full text makes clear that the information that Mao supplied to Stalin was full of fabrications. These included the claim that the US had also used “gases” (in other words, chemical weapons), that the US had used artillery to distribute biological weapons (a very implausible suggestion for multiple reasons, at least one of which is that the US had no artillery munition to distribute BW at the time of the Korean War), and that the US was using North Korean POWS for BW experiments. The last charge, again presumably modeled on Japanese behavior during World War II in China, became an important element of Chinese propaganda in the subsequent months.[32] Stalin’s reply was brief:

23 February 1952

To Comrade Mao Zedong

Your telegram of 21 February has been received.

In response to the criminal actions of the American imperialists, who have embarked on bacteriological warfare in Korea, it is essential for the anti-imperialist camp to take serious countermeasures.

We agree with the plan of measures you have proposed for both the [North] Korean and the Chinese governments, as well as for the World Council for the Supporters of Peace.

The Soviet Government, for its part, will actively support these measures.

With greetings,

FILIPPOV [Stalin][33]

Two messages then follow from Zhou Enlai to Stalin on March 7 and March 10 stipulating what kinds of assistance China needed to cope with the medical situation of its troops in the field. This included 600 tons of DDT, various vaccines (the numbers of million doses for each required), and expert medical and epidemiological personnel and field laboratory equipment. Stalin’s reply on March 14 specified exactly what the USSR would send to China. [34] The quantities were in every instance less than Zhou had requested (for example, the USSR would send only 100 tons of DDT). The last of the documents published by RGASPI, a message from Mao to Stalin dated June 24, 1952, reads:

24 June 1952

Comrade Filippov!

Upon arriving in Beijing [with] the delegation of the International Committee to Investigate the Facts of Bacteriological Warfare, created by the World Peace Council, the Soviet delegate Zhukov, having become familiar with the exhibits and materials organized here by us, proposed to invite the corresponding member of the USSR Academy of Sciences Petrichev, the parasitologist Teplov, the specialist on viral diseases Levkovich, and a specialist on entomology to arrive specially in Beijing by air to provide assistance to us in preparing the report of the International Committee…

I hope that these four specialists will be sent to Beijing as soon as possible…

Mao Zedong[35]

These documents prove that correspondences between Stalin, Mao and Zhou do exist, contradicting decades of denials by Chinese military historians that there were no such documents. Unless they were all deliberately destroyed by the Chinese government, they must exist in Chinese archives that hold Mao and Zhou’s Korean War correspondence with Stalin.

In addition to the RGASPI records, two documents obtained from RGANI in 2016, by authenticating three of the files which were published in Bulletin 11, provide further evidence that China’s allegations were in fact fraudulent.[36] One of them is a standard cover sheet listing an issue considered by the CPSU Presidium with a notation on the back indicating how the issue got placed on the Presidium’s agenda. This particular sheet is for the second issue considered by the CPSU Presidium at its session on April 24, 1953.[37] The cover sheet verifies that the CPSU Presidium discussed the allegations against the United States. The second record lists all of the issues (30 in total) considered by the CPSU Presidium at its six sessions from March 13 through April 24, 1953.[38]  According to the register, two of issues considered at the session on April 24 concerned the biological warfare allegations.  The listing of the second issue provides further corroboration that Protocol No. 6 of the Meeting of the Presidium of the CC CPSU addressed the MVD Note on the Results of the Investigations into the Reports of Former Advisers to the Ministry of State Security and DPRK Ministry of Foreign Affairs, comrades Glukhov and Smirno.


What remains to be ascertained about the history of the Korean War BW allegations? In 1998, given what was known about the relationship between Mao, Stalin, and Kim Il Sung and the Central Committees of the USSR and China, it seemed inconceivable for most scholars to imagine that it was not the USSR that had been the instigator and central actor in formulating the Korean War BW allegations. Now that conception at least has to be reconsidered. The critical question is: who decided on what day that Chinese and Soviet military personnel assisting them would place packets of various insects in the snow to be found? Mao? The Chinese Generals? Zhou Enlai? Or Stalin? It certainly was not Wu Zhili. The medical and entomological specialists that were members of the Chinese Commission had not yet been recruited and had not yet been sent to the combat zone. And who authorized the astonishing telegram that Wu received in the very first days after January 29, 1952 from the Central Committee saying that “the enemy had not carried out biological warfare, but that we could still take advantage of this to reinforce health work”?

A Chinese historian provides the following chronology for several critical events between February 19 and February 22, 1952:

February 19, the Chinese General Staff sends its report of finding insects to Mao and Mao designates Zhou Enlai to take responsibility for the subject. In what would appear to be a remarkably intense and efficient staff effort, Zhou presents Mao with a six-point plan of what to do on the very same evening, point 6 of which was “Send a report of the event by telegram to the Soviet Union, asking for its instant assistance.”

February 21: Mao sends a telegram to Peng Dehuai, commander of the Chinese military forces in North Korea, the same day that he sends his message to the North Korean government. Mao’s telegram states that China “…must denounce in front of the people in the world and mobilize international opinion to oppose.”

February 22: The North Korean Foreign Minister makes his public statement.[39]

Unfortunately the chronology only begins a full 21 days after January 29, which is an ocean of time in which to decide and organize a conspiracy as a part of the war effort against the US. In fact it may have been planned well before January 29, 1952, given the Chinese and North Korean allegations in the first half of 1951. There was lots of time for someone to think of “a better way” to carry out a campaign of BW allegations against the US a second time. In fact, who thought of the 1951 campaign of BW allegations? Should one assume on the basis of the preceding that it may again have been a Chinese initiative? Or did Soviet disinformation operatives conceive of it? Either way, there must again be high-level correspondence between the three parties concerning the early 1951 BW allegations against the US. Finally, what was it that Mao wanted to be “denounced” in his message of February 21, and what was to be “opposed,” was left unnamed. On February 21, we know that Mao had already sent his first long cable to Stalin.

Are there other communications between Beijing and Moscow, and/or between the CCP and the PLA General Staff during these key days that have still not been disclosed? Is it possible that communications and planning had been taking place for weeks before at lower levels, between Soviet and Chinese intelligence agencies, elaborating the plans of a fabricated BW allegations campaign? These are all critical questions to which the answers are still unknown. Nevertheless, on the basis of both new and old sources, the main story is indisputably clear: the Korean War BW allegations against the US, an accusation of the use of a weapon of mass destruction, were false, a grand piece of political theater.

Milton Leitenberg was trained as a scientist and began work in the field of arms control in 1966. In 1968, he was the first American recruited to work at the Stockholm International Peace Research Institute (SIPRI). He was subsequently affiliated with the Swedish Institute of International Affairs and the Center for International Studies Peace Program at Cornell University. He has been at the School of Public Affairs, University of Maryland since 1989, as Senior Research Scholar for the past 20 years. 

A shorter version of this Working Paper appears as Milton Leitenberg, “A Chinese Admission of False Korean War Allegations of Biological Weapon Use by the United States,” Asian Perspective 40, no. 1 (January-March 2016): 131-146.

The author is extremely grateful for the assistance of Drew Casey, Jiehong Lou, Torbjorn Loden, Melvin Gurtov, and Charles Kraus for translations of the recent Chinese language publications. Svetlana Savranskaya and Mark Kramer both brought the new Russian sources to the attention of the author, with Mark Kramer graciously providing the translations of documents from the Soviet Russian State Archives of Social and Political History (RGASPI). This paper could not have been prepared without their assistance. 

Document Appendix


Suggested Citation: Milton Leitenberg, "China’s False Allegations of the Use of Biological Weapons by the United States during the Korean War," Cold War International History Project Working Paper 78 (March 2016), accessed at

[1] These and other details are provided in Milton Leitenberg, “New Russian Evidence on the Korean War Biological Warfare Allegations: Background and Analysis,” Cold War International History Project Bulletin 11 (Winter 1998): 180-199. The early portion of this paper is drawn largely from that publication. As the 1998 publication contains very detailed references, these are not repeated again here. Readers are directed to the earlier publication for sources.

See also Kathryn Weathersby, “Deceiving the Deceivers: Moscow, Beijing, Pyongyang and the Allegations of Bacteriological Weapons Use in Korea,” Cold War International History Project Bulletin 11: 176-180.

[2] Leitenberg, “New Russian Evidence on the Korean War Biological Warfare Allegations.” The reference will not be repeated for the details provided on the pages which follow.

[3] Milton Leitenberg, “False Allegations of US Biological Weapons Use during the Korean War,” in Anne L. Clunan et al, eds., Terrorism, War or Disease, Unravelling the Use of Biological Weapons (Stanford, CA: Stanford University Press, 2008): 120-143.

[4] United Nations Security Council, “Letter from the Permanent Representative of the Union of Soviet Socialist Republics, President of the Security Council, Dated 30 June 1952. Annex I: International Association of Democratic Lawyers Appeal to the Security Council,” S/2684/Add. 1, 30 June 1952.

The ADL report stated that, “proceeding in a vein which surpasses the savagery of Hitler Germany and Hirohito Japan in the last war, the American invaders, by a systematic spreading of smallpox, cholera and plague germs over North Korea, have shocked and horrified the entire world.”

Claims by Western supporters of the Chinese allegations were even more extravagant. The Rev. James Endicott, head of the Canadian Peace Council, “claimed use of radioactive dust, wiped out several villages.” Notes by Joseph Needham of a meeting held in the UK on April 25, 1952, to hear the results of the ADL report. See Tom Buchanan, “The Courage of Galileo: Joseph Needham and the ‘Germ Warfare’ Allegations in the Korean War,” History 86, no. 284 (October 2001): 509, doi: 10.1111/1468-229X.00203.

[5] “Qin Chao Mei jun jinxing xijun zhan ji wo caiqu cuoshi qingkuang de baogao” (“Report on American Invaders Using Bacteria Weapons and Our Responsive Action”), February 28, 1952, Nie Rongzhen junshi wenxuan (Selected Military Papers of Nie Rongzhen) (Beijing: People’s Liberation Army Press, 1992), 365-366. Most of the memorandum deals with other issues, such as pre-planned vaccines and gas defense for Chinese troops and anticipation of nuclear weapons use by the United States.

[6] Report of the International Scientific Commission for the Investigation of the Facts Concerning Bacterial Warfare in Korea and China (Beijing: Foreign Languages Press, 1952).

[8] Tibor Meray, “The Truth About Germ Warfare,” a series comprised of twelve articles published in the Parisian daily paper, Franc-Tireur, between May 6 and May 19, 1957, accessible at See also Milton Leitenberg, “The Korean War Biological Weapon Allegations: Additional Information and Disclosures, Asian Perspective 24, no. 3 (2000): 159-172.

[9] Meray, “The Truth About Germ Warfare” (emphasis added).

[10] Personal communication to Milton Leitenberg. Appraisals of equivalent substantive meaning were also obtained from two retired Soviet generals, independently, by two colleagues, one of them a Soviet-era arms control expert.

[11] These papers and the various arguments that they made, at least those published up to 1998, were summarized in Leitenberg, “New Russian Evidence on the Korean War Biological Warfare Allegations.”

[12] “Special Estimate: Communist Charges of US Use of Biological Warfare,” SE-24, March 25, 1952; Declassified in 2000. Preparation of the study began on March 7, 1952.

[13] “NSC-62: Chemical Warfare Policy,” A Report to the National Security Council by the Secretary of Defense, February 1, 1950, Record Group 273, National Archives and Records Administration. The section on US BW policies and capabilities is taken from Milton Leitenberg, “False Allegations of US Biological Weapons Use during the Korean War.”

[14] “NSC-147: Analysis of Possible Courses of Action in Korea,” December 28, 1953, Foreign Relations of the United States, 1952-1954,                 Volume XV, Korea, Part 1 (Washington, DC: Government Printing Office, 1984), accessible at

[15] Copy of President Truman’s letter, July 25, 1969, supplied to the author by Representative Robert Kastenmeier in 1969, accessible at

[16] Certificate, Brigadier General H.L. Hillyard, US Army, Secretary of the Joint Chiefs of Staff, April 21, 1959, CCS 3260: Chemical, Biological etc. 1959, Record Group 218: Records of the Joint Chiefs of Staff: Central Decimal File, Box 032, US National Archives. This information was kindly supplied by the historian, John van Courtland Moon, in a personal communication in 1998.

[18] US Department of the Army, US Army Activity in the US Biological Warfare Program, vol. 2, February 24, 1977.

[19] “Telegram from Mao Zedong to I.V. Stalin (Filippov) about the Use by the Americans of bacteriological weapons in North Korea (Excerpt),” February 21, 1952, Archive of the President of the Russian Federation, translated by Kathryn Weathersby, accessible at

[20] “Resolution of the Presidium of the USSR Council of Ministers about Letters to the Ambassador of the USSR in the PRC, V.V. Kuznetsov and to the Charge d’Affaires for the USSR in the DPRK, S.P. Suzdalev,” May 2, 1953, Archive of the President of the Russian Federation, translated by Kathryn Weathersby, accessible at

[21] “Telegram to V.M. Molotov from Beijing from the USSR Ambassador to the PRC, V.V. Kuznetsov,” May 11, 1953, Archive of the President of the Russian Federation, translated by Kathryn Weathersby, accessible at

[22] “Telegram from the USSR Charge d’Affaires in the DPRK, S.P. Suzdalev to V.M. Molotov,” June 1, 1953, Archive of the President of the Russian Federation, translated by Kathryn Weathersby, accessible at

[23] Since the 1998 publication of the Soviet Central Committee documents, there have been at least eight North Korean or proxy publications and at least eight Chinese or proxy publications that maintain the validity of the old Korean War charges of biological weapon use by the US during the war.

[24] Wu Zhili, “1952nian de xijun zhan shi yi chang xujing” (“The Bacteriological War of 1952 is a False Alarm”) Yanhuang Chunqiu no. 11 (2013): 36-39, accessible at

[25] The 1988 book by Halliday and Cumings provides a somewhat different description of Mao’s remark to the ISC members, reporting that Mao said “Don’t make too much of all this. They’ve tried using biochemical warfare, but it hasn’t been too successful. What are all these uninfected insects they are dropping?” The authors presumably obtained their version of Mao’s comment from one of the ISC members, most likely the Italian member, Franco Graziosi. It should probably be considered less reliable. In addition, if Mao had really said “uninfected insects, the ISC should simply have ended its work directly. See Jon Halliday and Bruce Cumings, Korea: The Unknown War (New York: Pantheon Books, 1988), 185.

[26] Shen Zonhhong et al, eds., Zhongguo renmin zhiyuanjun kang Mei yuan Chao zhan shi (The History of the War to Resist US Aggression and Aid Korea) (Beijing: Junshi kexue chubanshe, 1988).

[27] Qu Aiguo, “Shi Mei jun de zuixing haishi Zhong Chao fangmian de ‘huangyan’: Guanyu kang Mei yuan Chao zhanzheng fan xijun zhan douzheng de lishi kaocha” (“Is it the US Military’s Crimes or the ‘Lies’ of the China-North Korea Side?: A Historical Investigation of the Anti-Germ Warfare Struggle during the Korean War”), Junshi lishi no. 2 (2008: 1-8, as well as the revised version of this essay published in Wenshi cankao no. 12 (2010): 74-81.

[28] In 2002, Zou Yunhua, then a “senior research fellow on arms control at the General Armaments Department of China” wrote a chapter titled “China: Balancing Disarmament and Development” in the book Susan Wright, ed., Biological Warfare and Disarmament, New Problems/New Perspectives (Boulder: Rowman & Littlefield Publishers, Inc, 2002).

Zou felt obliged to include a section in her paper titled “U.S. Biological Warfare against China and North Korea” and stated that it drew on “several restricted (neibu) publications, in particular a history written by members of the Chinese Academy of Military Science and published in 1988.” According to Zou, the authors of this neibu study “had access to the China State Central Archives and the Archives of the Peoples Liberation Army.” Zou not only repeated all the by then discredited BW allegations against the US, but also in one of her endnotes tucked away a reference to a critique of the “Milton Leitenberg” paper published in the Cold War International History Project Bulletin, but could not manage to reference that paper directly or explain what it contained. The editor of the book permitted that to stand.

[30] About two-thirds of the documents, some in abbreviated form, were published in the Japanese newspaper Sankei Shimbun.

[31] Китайская Народная Республика в 1950-е годы : сборник документов в двух томах (Памятники исторической мысли, 2010), 132-152 passim.

[32] It is important to note that there is nearly a full month between the beginning of Wu Zhili’s narrative on January 29 and Mao’s message to Stalin on February 21. Other communications that Wu would not have been privy to—and, presuming they do exist—may have been exchanged on the subject between Soviet and Chinese officials at various levels, and not have been published by the Russian archive.

[33] RGASPI, F. 558, Op. 11, D. 342, L. 92, translated by Mark Kramer, accessible at

[34] Stalin’s message also indicates that there had been an additional cable from Zhou, on March 8.

[35] RGASPI, F. 558, Op. 11, D. 343, Ll. 51-52, translated by Mark Kramer, accessible at

[36] See Weathersby, “Deceiving the Deceivers,” 182-183. The three files are, respectively, “Memorandum from L.P. Beria to G.M. Malenkov and to the Presidium of the CC CPSU,” April 21, 1953, accessible at; “Memorandum from V.M. Molotov to Members of the Presidium of the CC CPSU,” April 21, 1953, accessible at; and “Protocol No 6 of the Meeting of the Presidium of the CC CPSU about the MVD Note on the Results of the Investigations into the Reports of Former Advisers to the Ministry of State Security and DPRK Ministry of Foreign Affairs, Cdes. Glukhov and Smirnov,” April 24, 1953, accessible at

[37] RGANI, F. 3, Op. 8, D. 24, Ll. 2, 2ob, translated by Mark Kramer, accessible at

[38] RGANI, F. 3, Op. 8, D. 24, Ll. 107-108, translated by Mark Kramer, accessible at