A total of 36 people are believed to have died at a Russian coal mine where a methane gas leak triggered three explosions and the collapse of the mine, officials said.

Russian emergency services said the dead included five rescue workers and a mine worker who were killed when the third explosion rocked the Vorkutaugol mine in Russia's far north Komi region.

The first two explosions struck on Thursday, killing four miners and trapping 26 others.

Mine director Denis Paikin said on Sunday that given the level of gas in the mine and the trajectory of the fire, which continues to rage, all of the missing miners are presumed dead.

At the time of the blast, about 110 miners were underground and 80 were rescued.