The other 12 have been taken to a hospital, Russian sources have said.
The ATR-72 turboprop aircraft was heading towards the oil town of Surgut across Siberia when it crashed. All four crew members on board, including two pilots, were killed.
Passengers killed on board the aircraft are all believed to be Russian.
Flight 120 disappeared from radar screens around 05:35 local time, after the pilot was forced to attempt an emergency landing, which failed. The plane hit the ground and burst into flames, and was found in a snowy field about 22 miles from where it took off in Tyumen.
Survivors were taken to a nearby hospital, and 8 of them are being operated on, according to Russian news sources. The black box recorders have been recovered from the aircraft, but no information has yet been released as to how this could have happened.
Russian air safety has been notoriously bad in the last few years, with 15 crashes last year killing 120 people. Although standards have improved recently, this incident will raise fresh questions about aircraft maintenance.