Rescue workers have been scrambled to save 83 people trapped in Russia's largest underground coal mine after two explosions killed at least 12 people and injured dozens more.
Among those trapped yesterday were rescue workers who had entered the Raspadskaya mine in Siberia after the first blast.
The second, more powerful explosion destroyed the main air shaft and all of the mine's above-ground structures, the governor of the Siberian region of Kemerovo told Prime Minister Vladimir Putin during a meeting with emergency officials.
No more rescue workers would be sent into the mine until the methane was pumped out for fear of further explosions, Governor Aman Tuleyev said.
More than 500 emergency workers from around the country struggled throughout the day to ventilate the mine and rebuild mine shafts so the search for those trapped could resume, said Valery Korchagin, spokesman for the Emergency Ministry in Kemerovo, about 2,000 miles east of Moscow.
“Our unit is ready to go on a reconnaissance mission as soon as the concentration of methane in the air is lowered. We hope this can happen by midnight local time (1700 GMT),” said Sergei Sharov.
The first blast, believed to have been caused by methane, hit the Raspadskaya mine just before midnight on Saturday and the second about three and-a-half hours later.
There were 359 workers below ground at the time of the first explosion, the Emergency Ministry said. A total of 58 people were injured.
Most managed to get out, but after the second blast, 64 miners and 19 rescue workers were trapped underground and all communication with them was lost, Emergency Minister Sergei Shoigu said during the meeting with Mr Putin, parts of which were televised.
“It's clear the situation is difficult,” Mr Putin said.
“We could even say very difficult, tragic. Dozens of people remain in the mine.
Their fate is unknown. And the saddest thing is that additional rescuers cannot be sent into the mine right away.”
He ordered emergency workers to use all means available to ventilate the mine as quickly as possible. The mine is 500 metres deep and has 220 miles of underground tunnels, Mr Tuleyev said.
The Raspadskaya mine produces about 8 million tons of coal a year, according to the company's website.
There was no immediate information on what set off the blast.
Mine explosions and other industrial accidents are common in Russia and other former Soviet republics, and they are often blamed on inadequate implementation of safety precautions by companies or by workers themselves.
In December, nine people were killed in an explosion at an iron ore mine in the Urals Mountains region which was blamed on faulty transportation of explosives.
The deadliest explosion in Russia's coal mines in decades happened in March 2007, when 110 miners were killed in Kemerovo.