Afghan security forces inspect the site of a U.S. airstrike in Kunduz city, north of Kabul, Afghanistan, on Friday.

But the US said it was a crash that happened shortly after midnight Thursday at Jalalabad air field, 125 km from the capital, Kabul.

An unknown number of people on the ground were also killed, said US Air Force Maj. Tony Wickman, spokesman for the 455th Air Expeditionary Wing. The passengers were civilian contractors working with NATO’s Resolute Support mission and were the only passengers on board, Wickman added.

The airmen were assigned to the 774th Expeditionary Air Lift Squadron, part of the 455th, and the plane, a Super Hercules, crashed “shortly after take-off wholly within the airfield,” he said.