Explosions at a coal mine in Russia's far north Komi region have killed four miners, and a further 26 are missing.

A methane gas leak late Thursday triggered two explosions and the collapse of the mine, according to the Tass news agency. At the time of the blast, 110 miners were underground. Eighty were rescued.

The Vorkutagol coal mining company said on Friday that fire is still raging inside the mine. Rescue efforts are continuing, but Russia's state emergency service has not been able to establish a line of communication with the trapped miners, according to Tass news reports.

The Russian investigative committee said it is looking into the explosion, and the Kremlin appointed a special commission to deal with it.