Key-Mirzavand, Iran ? Heavy snow and dense fog Wednesday prevented rescue workers from recovering dozens of bodies from a mountain in western Iran where a leased Russian-built airliner crashed with 117 people on board.

The Tu-154 Tupolev airliner, operated by state-owned Iran Air Tours, went down in bad weather Tuesday morning outside Khorramabad, 230 miles southwest of Tehran, according to Iranian accounts.

Dozens of ambulances and cars belonging to Iran's Red Crescent remain parked at the foot of the Sefid Kouh mountains where a plane crashed on Tuesday. All 118 passengers and crew on board the plane are believed dead.

The plane carried 105 passengers and 12 crew. All were presumed killed, Iranian officials said.

Fifteen search parties headed up into the snow and fog that covered the bitterly cold reaches of the Sefid Kouh, which means white mountains in Persian.

“Some rescue teams returned from the crash site, and others have remained. They reported seeing dozens of bodies; some were mutilated. There is no possibility of retrieving any of the bodies today,” said Behrouz Goudarzy, deputy governor general of Lorestan province.

Helicopters were brought in because of the rough terrain that left at least three rescuers with broken bones, officials said.

A single helicopter spotted more than 40 bodies, but the team could not land and was forced to return to base when the weather turned bad, state-run radio reported.

Hamid Fouladvand, an official who reached the crash site by car and on foot Tuesday, described the grim scene.

“I saw dozens of bodies scattered deep in the valley. I also saw pieces of the plane. Wolves and bears were in the area and if the bodies aren’t collected soon, they will be eaten,” he said.

Weather forecasts called for more snow. “Search helicopters will remain grounded at least until Friday morning,” Goudarzy said.

Overnight, bulldozers cut a path from Key-Mirzavand, the village nearest the crash site, to the foot of the mountain, where the army, paramilitary Revolutionary Guards and the Red Crescent set up a base with more than a dozen tents.

A dozen relatives of the victims gathered at the operations base, 15 miles west of Khorramabad, the capital of Lorestan province.

Flight 956 lost contact with the Khorramabad airport control tower minutes before crashing. The cause of the disaster wasn’t known.

Nasrin Shafiiyan, whose husband, Houshang, was on the plane, said the crash was the fault of “the stupid incompetent officials who go and collect secondhand … planes from all over the former Soviet countries. What is this garbage they buy or rent?”

Russian aviation experts were sent to Iran to assist the investigations, according to Russia’s ITAR-Tass news agency.

In Moscow, Tupolev chief designer Aleksandr Shingart told Ekho Moskvy radio that the plane received a “proper” routine service in January.

Since the 1979 Islamic revolution that severed ties with America, Iran has been forced to supplement its fleet of aging Boeing and European-made Airbus airliners with planes bought or leased from the former Soviet Union.