How did the U.S. bomb a Doctors Without Borders (MSF) hospital in Kunduz, Afghanistan? The group and the world have questions, and the U.S. government has answers—several of them, with the latest coming from General John Campbell in a Senate hearing Tuesday morning.

“The hospital was mistakenly struck,” he said. “We would never intentionally strike a medical facility.”

Following the bombing on Saturday, a U.S. military spokesman on the ground in Afghanistan said that an airstrike “may have caused collateral damage to a nearby medical facility,” but the U.S. didn’t acknowledge hitting the hospital. The backlash against that was fierce, with MSF angrily rejecting that as inadequate for the deadly incident that killed 22 people.

Next, Defense Secretary Ash Carter admitted in a statement that the hospital had been hit in a “tragic” accident.

On Monday, Campbell revised the official narrative, saying the U.S. was simply carrying out a strike requested by Afghan fighters on the ground. “We have now learned that on October 3rd, Afghan forces advised that they were taking fire from enemy positions and asked for air support from U.S. forces,” he said. “An airstrike was then called to eliminate the Taliban threat and several civilians were accidentally struck.”