The United States on Tuesday carried out military strikes against three facilities in western Iraq associated with Iran-linked militias that American officials say attacked a major base in Iraq on Saturday, according to the Pentagon’s Central Command, injuring at least four U.S. service members.

The American strikes near Iraq’s border with Syria on Tuesday hit headquarters, training locations and storage areas for rockets, missiles and drones belonging to the Kataib Hezbollah militia and other Iran-affiliated groups in Iraq, according to Central Command.

“These precision strikes are in direct response to a series of escalatory attacks against U.S. and coalition personnel in Iraq and Syria by Iranian-sponsored militias,” Defense Secretary Lloyd J. Austin III said in a statement.

The attack against Al Asad Air Base in Iraq on Saturday was the latest and the most serious of about 151 such rocket and missile strikes directed at U.S. troops based in Iraq and Syria since Israel’s war against Hamas in Gaza started.