The U.S.-led coalition began bombing the Islamic State – also known as ISIS, ISIL, or Daesh – after the group seized large swaths of territory in Iraq and Syria in mid-2014. A dozen nations have been involved in airstrikes, although the United States has carried out more than seventy percent. The number of airstrikes increased throughout 2015, helping local forces regain control of strategic areas: In Syria, a Kurdish militia retook Kobani. In Iraq, Iraqi and Kurdish forces recaptured Ramadi, Sinjar, Baiji, and Tikrit. In 2016, the U.S. coalition increasingly targeted the areas around Raqqa, the ISIS capital in Syria, and Mosul, its stronghold in Iraq. By April 2016, the coalition had conducted more than 11,000 airstrikes, forcing ISIS to retreat from 40 percent of its territory in Iraq and 10 percent of its territory in Syria.

Pentagon officials emphasize that airstrikes alone will not defeat the Islamic State. The White House has refrained from deploying large numbers of ground troops, instead focusing on training, equipping and advising local forces. In 2014, the Pentagon launched a program aimed at training thousands of Syrian rebels. But by October 2015, the program was shut down after fielding only 150 fighters. The program was revamped and relaunched in April 2016. The following is a timeline of U.S. actions against ISIS since 2014.


August 9: The U.S.-led coalition begins airstrikes on ISIS targets in Iraq.

September 17: The House of Representatives votes to give the U.S. military authority to train and arm Syrian rebels, with a vote of 273-156.

September 22: The U.S.-led coalition begins airstrikes on ISIS targets in Syria.

September 25: Pentagon Press Secretary Rear Adm. John Kirby predicts that ISIS will adapt to U.S. airstrikes and that the United States will need “competent partners” on the ground to combat the Islamic State. He also emphasizes the need to “limit civilian casualties or collateral damage as much as possible.”

An EA-6B Prowler lands aboard an aircraft carrier after conducting airstrikes on ISIS targets on Sept. 23, 2014

October 7: The cost of U.S. military operations against ISIS reaches $1.1 billion.

October 15: The Pentagon designates the campaign against ISIS “Operation Inherent Resolve.”

November 4: Pentagon officials announce that they are working towards establishing a program to train and equip moderate Syrian opposition forces.


January 22: U.S. officials estimate that U.S. and coalition airstrikes have killed around 6,000 ISIS fighters.

January 26: Kurdish fighters, with the help of U.S. and coalition airstrikes, drive out ISIS militants from the Syrian border town of Kobani after a four-month battle.

January: The Pentagon begins investigating allegations of civilian casualties caused by U.S. airstrikes.

February: The White House steps up efforts counter extremist messaging on social media, working with the private sector and civil society groups. It also announces plans to designate a special envoy to focus on countering ISIS messaging.

March 3: U.S. officials estimate that U.S. and coalition airstrikes have killed around 8,500 ISIS fighters.

A U.S. soldier trains Iraqi soldiers at Camp Taji, Iraq on March 24, 2015.

April 1: Iraqi forces seize Tikrit from ISIS.

June 5: The Pentagon acknowledges that around 75 percent of aircraft return from missions without dropping bombs, in part because of difficulties isolating targets and the risk of civilian casualties.

June 7: Iraqi forces seize Baiji from ISIS.

June 13: A U.S. airstrike hits a gathering of al Qaeda members in Ajdabiya, Libya, targeting al Qaeda leader Mokhtar Belmokhtar. It is the first U.S. strike in Libya since 2011.

June 16: Kurdish forces seize the border town of Tal Abyad from ISIS, depriving the group of a key supply route.

June 18: The cost of U.S. military operations against ISIS reaches $2.91 billion.

October 9: The Pentagon’s program to train Syrian rebels – which cost $500 million annually – was shut down after fielding only 150 rebels. The goal had been to train 3,000 fighters by December 2015.

October 22: A U.S. soldier is killed during a rescued mission at an ISIS-controlled prison in northern Iraq. He is the first American soldier killed in action in Iraq since military operations resumed in 2014.

October 30: The White House announces that up to 50 special operations forces would be deployed to northern Syria to assist opposition forces. White House Press Secretary Josh Earnest denies that the deployments signal a shift in strategy, emphasizing that “These forces do not have a combat mission.”

November 7: Defense Secretary Ash Carter says that the United States needs “much more than airstrikes” to defeat ISIS, including successfully training local forces so that gains against ISIS are sustainable.

November 13: Kurdish forces capture Sinjar from ISIS in Iraq, and U.S.-backed rebels seize al Hawl from ISIS in Syria. A U.S. airstrike hits an ISIS base in Derna, Libya. Military officials believe the strike killed Abu Nabil, a former al Qaeda operative and a top ISIS leader in Libya.

December 1: Defense Secretary Ash Carter announces that a “specialized expeditionary targeting force” of around 200 troops would be sent to Iraq.

Ash Carter
Carter testifies before the House Armed Services Committee on Dec. 1, 2015

December 26: U.S.-backed rebels seize the Tishreen Dam from ISIS in Syria.

December 27: Iraqi forces seize Ramadi from ISIS in Iraq.


January 8: The Department of Justice and Department of Homeland Security introduce a new task force to counter violent extremism. The State Department also establishes a new center to undermine extremist messaging.

January 21: Defense Secretary Ash Carter outlines three goals in the U.S. and coalition military plan against ISIS: target its strongholds in Raqqa and Mosul, combat emerging ISIS affiliates worldwide, and protect other nations from ISIS attacks.

February 17: U.S. officials estimate that airstrikes have killed at least 26,000 ISIS fighters.

February 19: U.S. airstrikes hit an ISIS training camp in Sabratha, Libya, killing at least 49 people. U.S. and British special forces were deployed to Libya in the preceding weeks, supported by drones and warplanes. But the Obama administration reportedly declined requests from U.S. military officials to attack ISIS’s stronghold in Sirte, Libya, preferring to focus on occasional strikes against high-profile ISIS leaders.

February 22: U.S. special operations forces help Syrian rebels retake the town of al Shaddadi from ISIS.

Two French F-2 Rafales aircraft fly over Iraq in support of Operation Inherent Resolve on Jan. 8, 2016

March: A State Department Inspector General report finds that one third of Iraqis believe the United States is supporting ISIS, and around 40 percent believe the United States is trying to destabilize Iraq.

March 17: Secretary of State John Kerry labels ISIS abuses as genocide. "We must recognize what Daesh [ISIS] is doing to its victims," he says.

March 19: A U.S. Marine is killed by an ISIS rocket attack at a base in Makhmur, in northern Iraq.

March 25: Defense Secretary Ash Carter and Chairman of the Joint Chiefs of Staff Joe Dunford claim that the momentum in Iraq and Syria has shifted to coalition forces. Carter announces that he believes the U.S. military killed Haji Imam, ISIS’s second-in-command.

April 1: Military spokesman Col. Steve Warren announces that the United States is training “dozens” of Syrian rebels to fight ISIS, in a revival of the training program that ended in October 2015.

April 5: Secretary of State John Kerry states that the United States “is definitively at war with ISIS.” Secretary Carter announces that the Defense Department’s Cyber Command has been brought into the efforts to counter ISIS.

Air Force pilots fly a KC-135 Stratotanker aircraft over Iraq on April 6, 2016.

April 12: Deputy Defense Secretary Bob Work says that ISIS is under “enormous pressure” and that “Every time we have gone after one of their defended positions in the last 10 months, we have defeated them. They have left. They have retreated.”

April: The CIA prepares a “Plan B” to supply more weapons to Syrian rebels after signs that the six-week-old ceasefire was beginning to collapse. The CIA began a covert program to supply small arms and ammunition to Syrian rebels in 2013.

April 11: The U.S.-led coalition launches a website,, intended to boost online messaging efforts.

April 13: The Pentagon announces that the fight against ISIS has moved into a second phase. According to military spokesman Col. Steve Warren, “we believe that by degrading them in phase one and then dismantling them in phase two, we believe that that will set up phase three, which, of course, is the ultimate defeat of the enemy.” Phase two centers on retaking the key ISIS strongholds of Mosul and Raqqa.

April 13: The U.S.-led coalition arms Kurdish forces with heavy weapons to boost fighting capabilities against ISIS.

April 15: The U.S. military deploys tactical aircraft capable of attacking ISIS’s communications systems.

April 20: U.S. military officials acknowledge that authority for airstrikes has been delegated from U.S. Central Command (CENTCOM) to commanders on the ground. The change could allow airstrikes to hit targets more quickly, without waiting for higher approval, but also risks greater civilian casualties.

April 20: President Obama authorizes the deployment of 217 additional troops to Iraq. The United States also plans to dispatch Apache helicopters to Iraqi forces and pay $415 million in salaries for Kurdish troops.

April 20: The Air Force deploys B-52 bombers to carry out airstrikes. It is the first combat deployment of that type of aircraft in Iraq since 1991.

April 22: The U.S. military acknowledges that U.S. airstrikes killed 20 civilians and injured 11 others between September 2015 and February 2016.

April 25: President Obama announces plans to deploy 250 special operations forces to Syria. He emphasizes that their role is to support local forces and that they are “not going to be leading the fight on the ground.”

May 2: A U.S. service member is killed in northern Iraq, becoming the third U.S. casualty since March 2015.

May 5: ISIS captures the Shaer gas field near Palmyra.

May 19: Iraqi forces retake the western town of Rutbah. “Although a small town, Rutbah has outsized strategic value” due to its location on the main route between Amman and Baghdad, according to Operation Inherent Resolve spokesman Col Steve Warren.

May 23:  Iraqi forces, aided by U.S. and coalition airstrikes, advance on Fallujah, which ISIS has held since 2014.

May 24: Kurdish forces backed by U.S. airstrikes launch an offensive on territory north of Raqqa, Syria.

June 10: Special Presidential Envoy for the Global Coalition to Counter ISIL Brett McGurk said in a briefing that airstrikes had helped local forces capture 10,000 square kilometers in Syria and 30,000 square kilometers in Iraq from ISIS. He added that ISIS had been forced to cut oil production by one third since late 2015, and fighters' salaries had been reduced by half.

June 26: The Iraqi army retakes Fallujah from ISIS.

Photo credits: U.S. Department of Defense