Nato did not confirm the cause of the crash but it comes as Afghan forces — backed by Nato special forces and US air support — pushed into the center of the northern city of Kunduz which was captured by the Taliban on Monday.
“Our mujahideen have shot down a four-engine US aircraft in Jalalabad,” Taliban spokesman Zabihullah Mujahid said on Twitter.
“Based on credible information, 15 invading forces and a number of puppet troops were killed.”
NATO has not given any details on the cause of the crash. Six U.S. soldiers and five civilian contractors were killed, said U.S. Army Colonel Brian Tribus.