The Antonov-124 aircraft, which has the biggest wingspan of any aircraft in the world, crashed into an apartment block with 64 flats, narrowly missing an orphanage in Irkutsk-2, a satellite town of Irkutsk, some 3,000 miles and five time zones east of Moscow. It was carrying two Sukhoi-27 fighter planes.
Preliminary figures put the death toll as high as 80 in the disaster, thought to have been caused by the failure of two engines on the left side of the plane at a height of about 230ft. Rescue workers, braving temperatures of around minus 20C, spent hours tackling a fierce blaze at the scene of the crash.
A Kremlin spokesman said President Boris Yeltsin was deeply shocked by news of the crash and had instructed Prime Minister Viktor Chernomyrdin to fly to Irkutsk.
Mr Chernomyrdin said on television that the tragedy was a double blow for Russia, following just days after a mining accident in which more than 60 men died in Novokuznetsk, in the Kuzbass region to the west of Irkutsk.
The crash is the latest in a long series involving former Soviet aircraft. Fifty passengers and crew died in March when the tail of their chartered Antonov-24 broke off in mid-air during a flight to Turkey. Aviation officials say 219 people died last year in 43 air accidents in Russian airspace.
Military prosecutors have launched a criminal investigation into yesterday's accident, Russian television said.