NATO (search) helicopters and hundreds of police officers struggled to reach the wreckage of an Afghan commercial airliner Sunday, three days after it rammed into a snow-covered mountain peak, apparently killing all 104 people on board.

Fog, freezing temperatures and up to eight feet of snow thwarted efforts to reach the crash site of the private Kam Air (search) Boeing 737-200, which was found Saturday about 20 miles east of Kabul (search).

Officials believe none of the 96 passengers and eight crew — including at least 24 foreigners — survived the crash, expected to be Afghanistan's deadliest commercial air disaster.

On Sunday, NATO said its helicopters ferried Slovenian mountain rescue teams to the site, some 11,000 feet up Chaperi Mountain, but by late afternoon had failed to land.

The alliance released a photograph of what appeared to be part of the plane's white tail fin jutting from the snow. No other wreckage or bodies could be seen.

"The landing zone is very difficult due to the steepness of the terrain as well as the snow," NATO spokeswoman Maj. Karen Tissot Van Patot said.

About 18 inches of snow fell overnight, adding to the 61/2 feet already covering the mountainside, and the temperature dropped to about 10, Patot said.

Gen. Mahbub Amiri, an Afghan police commander coordinating the search from a village at the mountain's base, said he had more than 300 officers in position but could not send them up the slopes because of poor visibility.

"For the time being, there is nothing we can do," Amiri said.

The plane flown by Kam Air, post-Taliban Afghanistan's first private airline, vanished from radar screens Thursday while approaching Kabul airport in a snowstorm from the western city of Herat.

The airline believes the plane turned toward the Pakistani border city of Peshawar, searching for an easier landing, but encountered more bad weather. There was no indication that the scheduled flight was hijacked or brought down by a bomb.

"Maybe the pilot was not familiar with the area and he was in a lower position than he should have been," said Feda Mohammed Fedayi, Kam Air's deputy director. "The only reason we can suggest at this time is the weather."

Afghan transport minister Enayatullah Qasemi said Saturday the cause of the crash remained a mystery, and U.S. Department of Transportation experts and representatives of the foreign victims would help investigate.

President Hamid Karzai was "deeply saddened" and prayed for the victims when the crash was confirmed, his office said in a statement issued Sunday.

Kam Air began flying in November 2003. Its flights on leased Boeing and Antonov planes are popular with Afghan businessmen as well as aid and reconstruction workers. However, there have been concerns about the safety of its planes and its routes through the mountains near Kabul.

Qasemi said the plane carried passengers from at least five foreign countries.

U.S.-based Louis Berger Group Inc. confirmed that two of its engineers took the flight. Company manager Fred Chace identified them as Mark Humphries, from Texas, and Gianluigi Barattin, an Italian citizen. Both were helping rebuild a key Afghan highway.

Five other Americans were believed on board, including three staff of Management Sciences for Health, a nonprofit group based in Cambridge, Mass.

At Italian U.N. worker and a navy captain also were feared lost, along with nine Turks and the eight crew members — six Russians and two Afghans.

The Afghan passengers included Gen. Qasi Mohammed, commander of the Herat border brigade, as well as the brigade's finance director and a bodyguard, said Gen. Abdel Wahab Walizada, the top army commander in Herat.

Afghanistan's most recent commercial crash occurred March 19, 1998, when an Ariana Airlines Boeing 727 slammed into a peak south of Kabul, killing all 45 passengers and crew.