Rescuers who reached the remote site found bodies scattered near the wreckage of Russia's first post-Soviet civilian plane on the sheer face of Mount Salak, outside the city of Bogor, south of Jakarta, officials said.
"We entered the area... and found the dead bodies, but we cannot say about the number," said Gagah Prakoso, spokesman for the national search and rescue agency.
"We haven't found any survivors," he said.
The twin-engine Superjet 100 vanished from radar screens on Wednesday, 50 minutes into what was meant to be a short flight to show off its capabilities to prospective buyers as Russia tries to rebuild its civilian jet industry.
Reports of the number on board varied, with local rescue officials saying the plane was carrying 46 people and Trimarga Rekatama, the company responsible for inviting the passengers, saying 50 were on board.
Those aboard were mostly Indonesian aviation representatives, but also included eight Russians -- four of them crew and four Sukhoi employees -- plus an American and a Frenchman, officials said.
They said a helicopter pilot spotted the plane's debris after rescuers resumed their operation at first light on Thursday, locating one part with the Sukhoi logo on the sheer face of Mount Salak, a dormant volcano.
Devastated relatives of those aboard the ill-fated aircraft had gathered at the Halim Perdanakusuma airport in Jakarta -- used for military and some commercial flights -- where the Sukhoi had taken off the day before.
Some wept quietly as friends tried to console them, while others sat in a state of shock, staring into the distance. Authorities took DNA samples to help in identification if remains were found.
A teary-eyed Yenni Cipta, 38, recalled that when her father, an aviation worker, had said farewell on Wednesday, he had jokingly told her children: "Grandpa is going to a faraway place."
Prakoso said that evacuation of the bodies by helicopter was being hampered by bad weather.
"The evacuation is still difficult. By land we'll need 12 hours and by helicopter it would take only 20 minutes, but the weather is impossible," the search agency spokesman said.
"We are preparing a helipad so that tomorrow (Friday) morning, with clear weather, we can evacuate them."
The Sukhoi Superjet, a new passenger aircraft, is crucial to Russia's hopes of becoming a major player in the modern aviation market, and the crash in Indonesia is the first disaster involving the type.
The demonstration flight was part of an Asian tour to promote the aircraft, which is a joint venture between Sukhoi and Italy's Alenia Aeronautica. It made its first commercial flight last year.
So far it is being flown by two airlines, Russia's Aeroflot and Armenia's Armavia, but orders have reportedly been confirmed with more, including Indonesia's Kartika Airlines and Sky Aviation.
At the Jakarta airport, Susan Sepang, 50, clutched a framed photograph of her 30-year-old daughter, an employee of Sky Aviation who was aboard the plane, as a worker inserted a cotton swab in her mouth for a DNA test.
The mountainous Mount Salak region rises 2,000 metres (6,500 feet) above sea level, some 80 kilometres (50 miles) southeast of Jakarta. Indonesian officials have said the Sukhoi descended to about 6,000 feet shortly before it vanished.
The debris was found on the side of Mount Salak about 1,800 metres (5,900 feet) above sea level, said Lieutenant Colonel Mukhlis, a local military commander.