WASHINGTON — A US military transport plane crashed at an airfield in Afghanistan shortly after midnight on Friday (1930 GMT on Thursday), killing all 11 people on board, the US military said, describing the crash as an accident. The cause of the crash at Jalalabad airfield was under investigation, a spokesman said, refusing to rule out the possibility that there may be dead or wounded on the ground. First responders were on the scene, he said. Six US military service members and five civilian contractors who were employed by the US-led international force in Afghanistan were killed in the crash. A spokesman for the Taliban militant movement seeking to topple the government said its fighters had shot down the aircraft, but the US military said there were no reports of enemy fire at the time. A statement from the 455th Air Expeditionary Wing at Bagram Airfield described it as “an accident,” without offering details. — Reuters