AIN AL-ASAD AIR BASE, Iraq — U.S. troops cleared rubble and debris from a military base housing American soldiers in western Iraq on Monday, days after it was struck by a barrage of Iranian ballistic missiles in a major escalation between the two longtime foes.

The Iranian attack was in retaliation for the U.S. drone strike near Baghdad’s airport Jan. 3 that killed a top Iranian commander, Gen. Qassem Soleimani.

An Associated Press crew touring the Ain al-Asad base Monday saw large craters in the ground and damaged military trailers as well as forklifts loading rubble onto trucks in an area the size of a football stadium. U.S. soldiers inspected portable housing units destroyed and burned by the missile attack.

The air base in Iraq’s western Anbar province is a sprawling complex about 110 miles west of Baghdad shared with the Iraqi military and housing about 1,500 members of the U.S. military and the U.S.-led coalition fighting the Islamic State militant group.

It was struck by Iranian missiles on Wednesday in Iran’s most direct assault on America since the 1979 seizing of the U.S. Embassy in Tehran. The attack raised fears of a wider war in the Middle East although both sides have since then indicated that neither side would seek further retaliation, at least in the short term.

The U.S. said no American soldiers were killed or wounded in the Iranian attack.

“There were more than 10 large missiles fired and the impact hit several areas along the airfield,” said Col. Myles Caggins, a spokesman for the U.S.-led coalition. He added that the explosions created large craters, knocked over concrete barriers and destroyed facilities that house dozens of soldiers.

Although no soldiers were killed, he said several were treated for concussions from the blast. Caggins added that troops received notification the missiles were on their way thanks to early warning systems, and troops were moved.

The Ain al-Asad Air Base was first used by American forces after the 2003 U.S.-led invasion that toppled dictator Saddam Hussein, and later saw American troops stationed there amid the fight against the Islamic State group in Iraq and Syria.

U.S. Army Lt. Col. Antoinette Chase told reporters the night of the attacks the troops were hunkered down in bunkers after they received advance warning, but could “feel everything shaking.” She said troops had conducted a drill on a similar attack the week before.

Qassim Abdul-Zahra and Ali Abdul-Hassan are Associated Press writers.