Indonesian rescuers say they have discovered bodies from a wrecked Russian jetliner on a near-vertical cliff of a dormant volcano south of Jakarta. But authorities say there are no signs of survivors among the estimated 50 people on board, and warn that recovery efforts were hampered Thursday by bad weather and the remoteness of the crash site.

Indonesian President Susilo Bambang Yudhoyono, speaking in the capital, said he is in direct contact with rescue teams.

“The airplane crashed at the edge of Mount Salak. I have spoken directly to our officer in the field. It was around 1.5 kilometers from the informed point of scene. An investigation must be done immediately and thoroughly. Search and rescue operations must prioritize finding people on board.”

A search and rescue agency spokesman (Gagah Prakoso) said rescuers were lowered early Thursday from helicopters hovering over the crash site. He said bodies will be placed in cargo nets and lifted from the scene.

Family members of the victims who had gathered at a Jakarta airport broke down in tears when they heard that the wreckage had been located.

The doomed jetliner, which was on a promotional sales tour, took off from Jakarta's Halim Airport shortly after 2 p.m. local time Wednesday with an entourage of prospective buyers, journalists and crew. It was expected to return in less than an hour. But the plane dropped in altitude from 3,000 to 1,800 meters and lost contact with air traffic control at Mount Salak, which is 2,200 meters high.

Authorities say it is not clear why the plane requested to descend or whether air controllers approved the maneuver.

Reports on the number of people aboard the plane had not been reconciled by Thursday evening. Local rescue officials said the plane was carrying 46 people, while the company who invited the passengers said there were 50 on board. The Russian embassy in Jakarta said there were 44 people on the plane.

Authorities say the 100-seat Sukhoi Superjet 100 plane, built by Russia in a move to boost its civil aviation industry, was on the second of two demonstration flights when it disappeared in the remote Bogor region.

The Itar-Tass news agency said the newly-minted plane recently performed demonstrations in Central and South Asia, including flights in Kazakhstan, Pakistan and Burma and had logged about 6,500 hours of flight time since its 2008 maiden launch.

The jetliner is currently in use with Russia's largest carrier, Aeroflot, and the Armenian carrier, Armavia.