A top U.S. commander in Afghanistan says the airstrike that the U.S. unleashed on a hospital over the weekend was a mistake.

Doctors Without Borders has demanded answers after its hospital in Kunduz, Afghanistan, was bombed in an airstrike that killed at least 19 people, including three children, and injured dozens of others.

The bombing began at 2:10 a.m. Saturday and continued even after Doctors Without Borders, also known as Médecins Sans Frontières (MSF), told Washington that it was happening close to the hospital.

Washington and Kabul had been informed of the GPS coordinates of the hospital on many occasions before the bombing, according to MSF.

The hospital, the only one of its kind in the region, was partially destroyed. It has treated nearly 400 wounded since fighting broke out last Monday, when the Taliban seized the city. More than 100 patients were in the hospital at the time of the bombing.

Some information in this report was provided by The Associated Press.