Two senior Iraqi army officers say a U.S. military plane has mistakenly fired at a gathering of tribal fighters and civilians west of Anbar, killing seven and wounding 11 others.
The officers said Saturday the U.S. forces had thought the victims in the al-Baghdadi area were militants.
An investigation is underway.
The incident came after U.S.-backed Iraqi forces earlier Saturday arrested an Islamic State group operative at his home, the officers said. At the time of the raid, a man in a nearby house tossed a grenade at the troops who returned fire, injuring him and his wife.
The officers spoke on condition of anonymity because they were not authorized to speak to media.