The first American reprisal on Iraqi soil in response to many recent insurgent drone and missile assaults, U.S. officials said. Early on Tuesday, U.S. soldiers were targeted at an airfield west of Baghdad. In self-defense, U.S. military aircraft reacted.

According to two U.S. sources, a close-range ballistic missile targeted the Ain al-Asad airfield, inflicting minor damage to infrastructure and injuring eight people.

The United States responded using an AC-130 aircraft that hit an Iranian-backed militia vehicle and a number of personnel involved in the attack.

There were several militant casualties, the officials said.

The U.S. had so far limited its response to numerous recent attacks against its forces in Iraq and neighbouring Syria, claimed by Iran-aligned Iraqi militia groups, to three separate sets of strikes in Syria.

The attacks began on Oct. 17 and have been linked by Iraqi militia groups to U.S. support for Israel in its bombardment of Gaza, following attacks by Gaza-based Palestinian militant group Hamas on Israel.