KABUL (AFP) -- An accident investigation team was on its way from the United States to Afghanistan Monday to help find out why a military helicopter crashed killing eight soldiers, the U.S. military said. The Chinook transport helicopter came down in darkness early Sunday in Zabul province, about 250 kilometers (150 miles) southwest of Kabul, after what the U.S.-led coalition said was a "sudden, unexplained loss of power and control."

Another 14 U.S. military personnel were wounded.

"There have been no indications that there was enemy fire. However, the incident is being investigated," coalition spokesman Lieutenant Colonel David Accetta told AFP.

A U.S. military investigation team was on its way but had not yet arrived in Afghanistan, he said.

Coalition soldiers were still at the crash site, which residents said was not far from the Kabul to Kandahar highway.

"We do still have the crash site secured. We will not leave the crash site unsecured for the safety of the locals and during the investigation," Accetta said. The coalition on Sunday advised Afghans to stay away from the area for their own safety, saying "recent reporting indicated a Taleban build-up for operations against the coalition forces in the region."

The investigation will try to determine "exactly what caused the power loss," said coalition media officer Captain Sharon Engelneier.

The crash was the first this year although there have been a string of similar ones involving foreign forces deployed to Afghanistan.

Most of the crashes have been accidents although in June 2005 a U.S. Chinook was shot down by a rocket-propelled grenade in the eastern province of Kunar, killing all 16 servicemen on board.