CHENARI, Afghanistan -- NATO helicopter gunships found the shattered wreckage of a missing Afghan airliner on a frigid mountain east of the capital yesterday, and officials said they believed none of the 104 people aboard could have survived the crash.
Six Americans were thought to have been on board, the US Embassy in Kabul said, double the number previously reported. Among the Americans were three employees of Cambridge-based Management Sciences for Health, who were in Afghanistan to help improve the country's public health system. They were Cristin Gadue, 26, who grew up in Burlington, Vt.; Amy Lynn Niebling, 29, of Somerville; and Carmen Urdaneta, 32, of Brookline.
A NATO helicopter spotted the plane's wreckage yesterday in mountains east of Kabul. The names of the other three Americans have not been released.
Afghan police struggled through deep snow to within sight of the scattered debris, but reported no sign of life. They were forced back by darkness and plummeting temperatures.
''So far we don't think there are any survivors," said Lutfullah Mashal, a spokesman for the Afghan Ministry of Interior. ''The plane is completely destroyed."
If all are confirmed dead, it would be the deadliest air disaster in Afghan history.
Officials said there was no indication that the scheduled flight, which was arriving from the western Afghan city of Herat, was hijacked or brought down by a bomb.
Afghan transport minister Enayatullah Qasemi said that the cause of the crash remained a mystery and that US Department of Transportation specialists as well as representatives of the foreign victims would help investigate.
NATO said two of its Dutch
Helicopters then dropped a Slovenian mountain rescue team to the scene, but Qasemi said nobody reached the wreckage before nightfall.
''Tomorrow, we plan to use helicopters to quickly start recovering the bodies," the minister said at a news conference. ''It's not an easy job and it will take time."
General Mahbub Amiri, an Afghan police commander who got as far as the village of Chenari, at the foot of the mountain, said 30 of his men got within a half-mile of the crash site. They saw no bodies among the pieces of plane jutting from the snow, but reported that wild animals and birds had been attracted to the scene.
''No way" could anyone have survived, Amiri said.
Kam Air began flying in November 2003, and its flights on leased Boeing and Antonov planes are popular with wealthy Afghans and also used by aid and reconstruction workers.
But there have been concerns about the safety of its planes as well as those of state-owned Ariana Airlines, as well as the approach through the mountains that ring Kabul. The airport only recently installed an electronic landing system and still relies on the main US base at Bagram, to the north, for radar.
UN staff are banned from using Kam Air or Ariana. But a spokeswoman confirmed yesterday that an Italian architect working for the UN was on board. Italian authorities said another Italian civilian and a navy captain were among the 96 passengers.
Beth Lee, a US Embassy spokeswoman, declined to give details on the six American passengers. Management Sciences for Health, the Cambridge group, said on Friday that its three employees were on board the plane.
Nine Turkish passengers, as well as the eight crew -- six Russians and two Afghans -- were also believed dead.