The United Nations on Friday called for an investigation into a North Atlantic Treaty Organization (NATO) airstrike that killed as many as 90 people—almost half of them reportedly civilians—during an attack on two hijacked fuel tankers. The massive airstrike on the two tankers commandeered by Taliban fighters set off a giant fireball, reigniting tensions between western forces and Afghans. The death toll included about 40 civilians who were siphoning fuel from the trucks, a senior Afghan security official told the Associated Press. The deputy chief of the U.N. mission, Peter Galbraith said he was “very concerned” by the reports of civilian casualties in the province of Kunduz. “Steps must also be taken to examine what happened and why an airstrike was employed in circumstances where it was hard to determine with certainty that civilians were not present,” he said, adding that a U.N. team would be sent to investigate.