An underground blast at a coal mine in the Komi region of northern Russia has killed 18 people, officials say.

Rescuers were brought in to search for people trapped below the surface at the Vorkutinskaya mine after the blast caused a tunnel collapse.

The explosion is thought to have been caused by a methane gas build-up. About 240 miners escaped to the surface.

Accidents are frequent in Russia’s huge coal mining industry despite recent efforts to improve safety.

The coal mine outside the city of Vorkuta in the Russian Arctic is operated by the steel-making giant Severstal.

An underground blast at a coal mine in the Komi region of northern Russia has killed 18 people

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