U.S. forces retaliate after attack in Iraq wounds American troops.

Ain al-Asad air base, which hosts U.S. forces in Iraq, has been targeted repeatedly by Iranian-backed groups. (Ayman Henna/AFP/Getty Images)

U.S. forces responding to an attack in Iraq over the weekend that wounded a small number of American personnel have struck three sites used by Iranian-backed militias there, the Pentagon said Tuesday.

Defense Secretary Lloyd Austin said in a statement that the operation, carried out at President Biden’s direction and “in direct response to a series of escalatory attacks” against U.S. and coalition personnel in Iraq and Syria, targeted Kataib Hezbollah. The militia is active in both countries and has claimed numerous attacks against Americans.

“The President and I will not hesitate to take necessary action to defend them and our interests,” Austin said. “We do not seek to escalate conflict in the region. We are fully prepared to take further measures to protect our people and our facilities. We call on these groups and their Iranian sponsors to immediately cease these attacks.”

The strikes, which occurred very early on Wednesday local time, marked the latest in what has become a regular drumbeat of military action as the militias seek to drive U.S. personnel out of Iraq and Syria. The militias are part of a broader network that receives Iranian training and weapons, and they have called for violence in response to Israel’s military campaign against Hamas, another group supported by Tehran.

On Saturday, the militants launched numerous ballistic missiles at Ain al-Asad Air Base, an Iraqi facility that houses U.S. troops. “Most” of the missiles were intercepted by U.S. air-defense systems on the base, officials have said, but some did reach the installation.