At least two coal miners were killed and 28 were missing at a mine in northern Russia after part of the structure collapsed.
Vorkutaugol, the owner of the Severnaya mine located in the northern region of Komi, said in a statement that 80 miners have been brought to the surface, and rescuers were trying to locate the others who were missing.
Emergency workers were quoted by the AFP news agency as saying that the mine was hit by a "pressure burst"on February 25 but no other details were given. .
Vorkutaugol is owned by Severstal, one of Russia's largest steel and mining companies.
Russian coal mines are among the more dangerous in the world, with many facilities lacking modern infrastructure.
An explosion at a mine in the Siberian region of Kemerovo in 2007 killed more than 108 miners.