"I can confirm an air strike at 2 am (2300 GMT) Saturday south of Mosul. We are showing there were five deaths," the spokesperson said.

An official from a joint US-Iraqi security center for Salahuddin province said the air strike targeted a suspected insurgent hideout in al-Aitha, a village on the border between Salahuddin and Nineveh provinces.

The official, speaking on condition of anonymity, put the death toll at 13, including four women and three children. He said the dead were all from the same family.

In May, a US air strike near Qaim, a town on the border with Syria, killed around 40 people. Locals claimed that the strike hit a wedding party, while the Americans said the house was a gathering point for "terrorists".

The US military bombed suspected insurgent targets in the former rebel stronghold of Fallujah from June until its November offensive to reclaim the city from insurgents.

US commanders acknowledged that their air campaign in Fallujah claimed the lives of some innocent civilians.