Thirty-six people are dead after Russia's worst coal mining accident in years, with authorities saying Sunday that they have abandoned rescue efforts in the northern town of Vorkuta.
"This is a terrible tragedy for Russia and for our coal industry," Deputy Prime Minister Arkady Dvorkovich said, after confirming that the 26 miners trapped in the mine were most likely dead.
Four miners were killed in an explosion on Thursday and another 26 were trapped after part of the mine collapsed.
Six rescue workers died on Sunday in a second explosion at the Severnaya mine, which resulted from an effort to free the trapped miners, taking the death toll to 36.
Citing Emergencies Minister Vladimir Puchkov, Russia's Interfax news agency reported that the rescue effort had been abandoned.
"We are forced to acknowledge that all the conditions at that section of the mine would not allow a person to survive," Puchkov said in comments carried by Interfax.
Sunday's explosion reportedly occurred at the exact site were the trapped miners are thought to have been.
The resulting fire 780 metres below the earth was to be extinguished by starving it of oxygen, said Denis Paikin, the technical director at Vorkutaugol, which runs the facility. He said the other alternative would be to partly flood the pit.
Eighty of the 110 men who were underground at the time of the accident were pulled to safety. Hundreds of rescuers were deployed to the scene, as well as specialists from Russia's Siberian mining centres of Kemerovo and Novokuznetsk.
Steel industry oligarch Alexei Mordashov, who owns Vorkutaugol, denied accusations that equipment for measuring gas levels had been tampered with. Trade union members had previously criticized safety standards at the mine.
Authorities say it is Russia's worst mining accident in several years.
A methane explosion at a mine in Ulyanovskaya in Siberia's coal-rich Kuznetsk Basin killed 110 in 2007.