An underground methane gas explosion has killed up to 18 miners at a coal pit in northern Russia.

Rescue workers said they had brought ten bodies to the surface so far at the Vorkutinskaya mine, owned by large Russian steel company Severstal.

Around 250 people had been at the pit at the time of the blast, about 800m below the surface, but most had escaped or been rescued, government officials said.

The explosion is likely to renew concerns about safety at Russia's ageing pits, where accidents are common, often because of such explosions, negligence or a failure to follow safety regulations.

The Interior Ministry put the death toll at 18, but the Emergencies Ministry said 16 had been killed and the fate of two others was not known.

The explosion was also a blow to Severstal, whose shares fell 2.2% in Moscow afterwards.

The blast, which affected only one of the mine's walls, is not expected to greatly affect output, which is approximately 1m tonnes a year.

A mine blast killed 110 people in the coal-mining region of Kemerevo in 2007 and another explosion in the same region in 2010 killed more than 60.

Russia's federal Investigative Committee said it had opened an investigation to check whether there had been any safety violations at the Vorkutinskaya mine, which has been in operation since 1973.