A US Army UH-60 helicopter crashed near Bagram air base in Afghanistan on Thursday, killing all four Americans aboard, the US military said.
"I can confirm that there are U.S. casualties and at this time this incident does not appear to be related to hostile action," Jim Wilkinson, director of strategic communications at Central Command headquarters, told reporters in Tampa, Florida.
He said that all four Americans aboard were killed when the helicopter went down several miles east of Bagram air base.
The helicopter, a transport aircraft known as "black hawk," andits crew were on a routine training mission when the tragedy took place, Wilkinson added.