At least one coal miner was killed and three others were missing after a blast at a Siberian pit on Wednesday, Russian news agency Interfax reported.
A miner's body was found after the blast at the Dzerzhinsky mine in the Kemerovo region city of Prokopyevsk, Interfax cited the provincial administration as saying.
It said the fate of three others was unknown.
A local law enforcement official said 101 of the 105 miners who had been underground at the time of the blast had made it to the surface, state-run RIA reported.
The privately owned mine is in a coal-rich section of central Siberia known as the Kuzbass.
Fatal accidents are frequent in Russia's ageing pits despite improvements in safety since the Soviet Union collapsed in 1991. Most accidents have been attributed to methane gas blasts, negligence or a failure to follow safety regulations.
A methane blast at a coal mine in northern Russia last February killed 18 miners.