An underground explosion which caused a tunnel collapse at a coal mine in the Komi region of northern Russia on Monday killed 18 people.
The explosion at the Vorkutinskaya mine is thought to have been caused by a methane gas build-up.
The emergencies ministry in Moscow said 259 miners were working underground at the time: 23 were in the shaft where the explosion took place at a depth of 800 metres.
About 240 men escaped to the surface.
The coal mine outside the city of Vorkuta in the Russian Arctic is operated by Severstal.