Kabul, Afghanistan ? American and Afghan troops hiked through rugged terrain Thursday to reach the wreckage of a civilian helicopter that crashed in the mountains of eastern Afghanistan, killing up to 16 people, including at least two Americans.

A purported Taliban spokesman claimed the rebels shot down the chopper, but a military official said it probably crashed by accident in bad weather.

The Russian-made Mi-8 helicopter – owned by the Afghan government and operated by a private company – crashed Wednesday about 25 miles northeast of Khost city, in a region where al-Qaida and Taliban militants are active. It was flying from the capital, Kabul.

Afghan and U.S. troops recovered 12 bodies and were searching for four others in the forbidding mountainous terrain, said Col. Tom Collins, a coalition spokesman. At least two American civilians were among those killed; the others were Afghans and foreigners, he said.

The Dutch military said two of its officers were killed in the crash – the first Dutch military fatalities in Afghanistan, where it has about 1,500 troops as part of a NATO-led, multinational security force.

Officials said there were no survivors. But there was some uncertainty about the number of people on board because the manifest listing passengers’ names had been kept on the aircraft, according to a Western diplomat.

The 12 recovered bodies were being flown to the main U.S. base at Bagram Air Base, near Kabul, for repatriation, Collins said. He said there was no indication yet what caused the crash, but a Dutch military official said it was probably an accident.

“It was in a mountainous region in very bad weather – rain and mist which reduced visibility. That points toward it being an accident such as flying into a mountain or something like that,” military spokesman Lt. Col. Nico van der Zee told The Associated Press.

He did not rule out the possibility of hostile fire.

In an e-mail to an AP reporter in Pakistan, Muhammad Hanif, who claims to speak for the Taliban, said its militants had shot down the chopper Wednesday afternoon with an unspecified “new weapon.”

Hanif’s ties to the Taliban leadership are unclear. In the past, claims of responsibility made in the name of the hard-line militia have sometimes proved false or exaggerated.