The US military struck three facilities in Iraq on Tuesday, targeting an Iranian-backed militia in retaliation for missile and drone attacks on American troops in Iraq and Syria over the past several days, Defense Secretary Lloyd Austin said.

The US strikes hit militia facilities in western Iraq, near the Syrian border, US Central Command said.

“At President Biden's direction, US military forces conducted necessary and proportionate strikes on three facilities used by the Iranian-backed Kataib Hezbollah militia group and other Iran-affiliated groups in Iraq,” Austin said in a statement. “These precision strikes are in direct response to a series of escalatory attacks against US and Coalition personnel in Iraq and Syria by Iranian-sponsored militias.”

The strikes came hours after the US said militants fired two one-way attack drones at the al-Asad Air Base, injuring US service members and damaging infrastructure. And they follow the militia's most serious attack this year on the air base, when they launched multiple ballistic missiles on Saturday at the western Iraq facility used by U.S. troops.

US Central Command said the attack targeted headquarters, storage, and training locations for rocket, missile, and one-way attack drone capabilities of the group.