An American general said Monday that Afghan forces requested the U.S. airstrike on a Kunduz hospital, which killed 22 people and injured 37 others. Gen. John F. Campbell reversed an earlier statement that the U.S. retaliated with the airstrike because insurgents from the hospital building opened fire on U.S. service members.

The attack on the Medecins Sans Frontieres (MSF) or Doctors Without Borders hospital took place Saturday, leaving 12 staff members and 10 patients dead. The aid group called for an independent investigation into the incident.

"We have now learned that on 3 October, Afghan forces advised that they were taking fire from enemy positions and asked for air support from U.S. forces," Gen. Campbell said, according to the Associated Press (AP).

"An airstrike was then called to eliminate the Taliban threat and several civilians were accidentally struck. This is different from the initial reports, which indicated that U.S. forces were threatened and that the airstrike was called on their behalf," the top commander of the U.S.-led NATO coalition in Afghanistan reportedly added.

However, MSF General Director Christopher Stokes said Campbell’s statements showed that the U.S. was trying to pass responsibility of the attack to the Afghan government.

“The reality is the U.S. dropped those bombs. … The U.S. military remains responsible for the targets it hits, even though it is part of a coalition. There can be no justification for this horrible attack. With such constant discrepancies in the U.S. and Afghan accounts of what happened, the need for a full transparent independent investigation is ever more critical,” Stokes said in a statement.

Hamdullah Danishi, the acting governor of Kunduz province, said the MSF hospital was a “Taliban base.” He added that the hospital campus was “100 percent” used by the insurgents.

MSF denied the allegations and called for an independent investigation into the attack. The organization also pulled out of the region following the airstrike.

The fight to retake Kunduz has shed light on the potential inability of U.S.- and NATO-trained Afghan forces to bring stability to the troubled region. On Monday, Taliban forces claimed to have recaptured  parts of Kunduz, hours after government forces gained brief control of the Afghan city, Al Jazeera reported.