Indonesian and Russian officials have pledged to cooperate in investigating what caused a Russian jetliner to crash into the side of a dormant volcano south of Jakarta earlier this week.

Officials say all of the up to 50 passengers on board likely died when the plane slammed into a nearly vertical cliff of Mount Salak at nearly 800 kilometers per hour on Wednesday.

Indonesian President Susilo Bambang Yudhoyono told families of the victims of the crash on Friday that Russia and Indonesia have agreed to work together on the rescue and recovery operation.

“Last night I spoke to the president of Russia, Vladimir Putin. We are both saddened by what happened. It was a Russian plane but the majority of passengers were Indonesian. President Putin conveyed his condolences. We have agreed to work together in searching, evacuating, and investigating what has happened.”

A team of rescue workers using climbing gear to scale the cliff have so far found at least 10 bodies at the scene of the wreckage. Bad weather has so far hampered efforts to remove the bodies using helicopters with cargo nets.

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.

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.