U.S. forces launched airstrikes on facilities on both sides of the Iraq-Syria border, the Pentagon said Sunday, in response to recent drone attacks on U.S. troops in the region carried out by Iran-backed militias.

Two militia locations in Syria were attacked, along with one in Iraq, Pentagon spokesman John Kirby said in a statement, which described the strikes as defensive in nature. Officials have said militias employing small, explosive-laden drones to attack regional U.S. personnel is one of the chief concerns for the U.S. military mission there.

At least five drone attacks on U.S. personnel have occurred in the region this year, according to a U.S. defense official who spoke on the condition of anonymity because of the sensitivity of the issue. One of the sites hit was used in the launch and recovery of armed unmanned aircraft. Another site was a logistics hub, the official added.

“President [Joe] Biden has been clear that he will act to protect U.S. personnel,” Kirby said. “Given the ongoing series of attacks by Iran-backed groups targeting U.S. interests in Iraq, the President directed further military action to disrupt and deter such attacks.”

The retaliatory strikes are in response to increasingly brazen and sophisticated attacks by Iran-backed militias that in recent years have relied more on rockets to attack U.S. troops and personnel.

Militiamen have turned at times to small, fixed-wing drones that fly too low to be picked up by defensive systems, military officials and diplomats have said. A common militant strategy is to attach explosives to the drones and crash them into targets, defense officials have said.


An April attack on a CIA hangar at the Irbil airport highlighted the uniquely frustrating problem of small unmanned aircraft sorties. A drone was detected within 10 miles of the site, officials have said, but it was lost after careening into a civilian flight path. Although no causalities were reported, the attack deeply concerned White House and Pentagon officials because of the covert nature of the facility and the sophistication of the strike.

A similar attack on an Iraqi air base in May raised worries that further attacks may trigger a cycle of retaliation among U.S. forces and Iran-backed forces that operate in the region. The U.S. assassination of Iranian Maj. Gen. Qasem Soleimani while he was in Iraq last year prompted a rocket attack on U.S. troops in the country, which led to scores of injuries but no deaths.

A U.S. contractor died after a smaller attack on the same air base in March. About 2,500 U.S. troops remain in Iraq.

The Pentagon has monitored the escalation of small-drone warfare after the Islamic State flew terrifying sorties of hobbyist drone aircraft against Iraqi troops in the battle to retake territory from the group.

Marine Gen. Frank McKenzie, the top U.S. military commander in the Middle East, told reporters on a Syria trip last month that the Pentagon is looking for ways to cut command-and-control links between a drone and its operator, improve radar sensors to quickly identify the threat as it approaches and find effective ways to bring down the aircraft.

“We’re open to all kinds of things,” he said, according to the Associated Press. “Still, I don’t think we’re where we want to be.”

The Biden administration in February ordered airstrikes against Iranian proxies in Syria, killing an undisclosed number of militants.

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The Washington Post’s Dan Lamothe, Mustafa Salim, Louisa Loveluck and John Hudson contributed to this report.