Doctors Without Borders says three members of its staff are dead and 30 missing after their hospital in the northern Afghan city of Kunduz was bombed.

The international aid organization said in a statement that the bombing took place at 2:10 a.m. Saturday. Afghan forces backed by U.S. airstrikes have been fighting to dislodge Taliban insurgents who overran Kunduz on Monday.

U.S. forces in Afghanistan acknowledged that they conducted an airstrike on Kunduz at 2:15 a.m. A spokesman, U.S. Army Col. Brian Tribus, said the strike "may have resulted in collateral damage to a nearby medical facility" and that the incident was under investigation.

Doctors Without Borders said its trauma center "was hit several times during sustained bombing and was very badly damaged."