An Afghan provincial government spokesman has alleged that a NATO airstrike killed at least three civilians and injured another in Afghanistan's Khost province Tuesday.

A spokesman for NATO's International Security Assistance Force, Lt. Col. Will Griffin, said ISAF is looking into the allegation.

Helicopters fired at houses in Khost's Nadershahkot district early Tuesday, killing a woman and two children and injuring a man, said Mubarez Zadran, spokesman for Khost's governor.

Afghan officials are investigating the incident, Zadran said.