Medical charity Doctors Without Borders says the number of people killed when their clinic in northern Afghanistan was bombed has risen to 30.

The group said Sunday the toll includes "10 known patients, 13 known staff and seven unrecognizable bodies." The Kunduz clinic was bombed by U.S. forces on Oct. 3.

The corpses were found in the debris and "have not been identified." They may include one staffer and two patients missing and presumed dead.

The bombing happened as troops battled to retake Kunduz from Taliban fighters who overran the city on Sept. 28.

Two military inquiries and an Afghan government probe are investigating why the hospital was bombed.

The head of U.S. forces in Afghanistan, Gen. John F. Campbell said it was a mistake. President Barack Obama has apologized.