(CNN) — The Pentagon is urgently looking at reports that six U.S. troops who died on Tuesday in southern Afghanistan might have been killed by enemy fire after their helicopter crashed due to mechanical failure, according to two senior U.S. officials.
Military investigators have a report that mortar fire hit the helicopter on the ground.
There was one survivor in the crash.
Earlier reports said that there was no enemy activity in the area at the time of the crash, according to NATO, and the U.S. defense official said early reports indicate the helicopter’s engine failed.
The troops were members of the NATO-led International Security Assistance Force.
The troops’ names have not been released. It is ISAF policy to allow national authorities to identify casualties.
™ & © 2013 Cable News Network, Inc., a Time Warner Company. All rights reserved.