Medical aid group Doctors Without Borders demanded an independent inquiry into an airstrike on its hospital in Afghanistan’s northern city of Kunduz, branding the Saturday attack a “war crime.” According to a statement released Sunday, the charity said it was “disgusted” by Afghan government statements justifying the strike, which left at least 22 people dead, including 12 clinic staffers. Defense Secretary Ashton Carter on Sunday vowed to carry out a full, transparent investigation into whether the U.S. military could be linked to the attack, which happened during a push by security forces to retake Kunduz from Taliban insurgents. The aid group, also known as Medecins Sans Frontieres, withdrew from Kunduz following the attack.