Kabul, October 6 (RHC)-- The top U.S. commander in Afghanistan has said that the deadly US air strike on a Doctors Without Borders hospital in the northern city of Kunduz was carried out at the request of Afghan forces.

The U.S. military had previously said that American troops were under Taliban fire and had called in the strike on October 3rd. It termed the hospital as "collateral damage." On Monday, U.S. General John Campbell told reporters: "We have now learned that on October 3, Afghan forces advised that they were taking fire from enemy positions and asked for air support from U.S. air forces."

The bombing, which killed 22 civilians, has prompted outrage around the world. Gen. Campbell now says the request was made to U.S. Special Forces advising and assisting Afghan Security Forces.

U.S. President Barack Obama said Saturday the Pentagon launched a "full investigation" into the deadly air strike. Campbell said three investigations are underway and "if errors were committed, we'll acknowledge them. We'll hold those responsible accountable and we will take steps to ensure mistakes are not repeated."

The medical aid group Doctors Without Borders (MSF), however, has called for an independent inquiry "under the clear presumption that a war crime has been committed." The charity said that despite frantic calls to military officials in Kabul and Washington, the hospital's main building was "repeatedly" struck for more than an hour.

The aid group says it has been forced to close its trauma center at the hospital.