WASHINGTON (AP) — The U.S. military conducted airstrikes on two locations in eastern Syria involving Iranian-backed groups, hitting a training location and a weapons facility, according to the Pentagon and U.S. officials. It marks the third time in a bit more than two weeks that the U.S. has retaliated against the militants for what has been a growing number of attacks on bases housing U.S. troops in Iraq and Syria.

In a statement, Defense Secretary Lloyd Austin said the strikes targeted sites near Abukama and Mayadin and were used by Iran’s Revolutionary Guard Corps as well as Iran-backed militias.

“The President has no higher priority than the safety of U.S. personnel, and he directed today’s action to make clear that the United States will defend itself, its personnel, and its interests,” Austin said.

A U.S. official said one site also included weapons storage. The official spoke on condition of anonymity to discuss details of a military operation.

The militant groups, many operating under the umbrella of the Islamic Resistance in Iraq, have carried out nearly 50 attacks since Oct. 17 on bases housing U.S. personnel in Iraq and Syria.

That was the day a powerful explosion rocked a Gaza hospital, killing hundreds and triggering protests in a number of Muslim nations. The Israeli military has relentlessly attacked Gaza in retaliation for the devastating Hamas rampage in southern Israel on Oct. 7. And a number of groups have vowed retaliation against the U.S. for backing Israel in the war against Hamas.

According to the Pentagon, about 56 U.S. personnel have been injured in the attacks in Syria and Iraq, but all have returned to duty. Their injuries are a combination of traumatic brain injury and other minor wounds.