A methane explosion at a coal mine in a remote part of Siberia has killed at least 78 people, Russian officials say.
Rescuers are racing against time to reach trapped miners
They said 83 miners, several of them injured, had been rescued after the blast at the mine, nearly 3,000km (1,850 miles) east of Moscow.
About 200 miners were believed to be underground at the time, and more than 40 are still trapped, officials said.
Russia's coal mines have a poor safety record. A methane blast at a Kemerovo coal mine killed 21 miners in 2005.
The blast happened at 1030 Moscow time (0730 GMT) at the Ulyanovskaya mine in Kemerovo region.
Kemerovo Governor Aman Tuleyev was quoted as saying the explosion occurred after a rockslide caused methane gas to build up in part of the huge mine.
He said that after getting as many people out as possible, the priority was to ensure that fire did not break out.
Local officials described current conditions down the mine as " very difficult".
According to Reuters news agency, rescue work was being hampered by thick smoke and roof collapses in horizontal shafts stretching for up to 5km.
A Reuters reporter who went to the mine said security guards prevented him from getting close.
Emergencies minister Sergei Shoigu has been ordered to the area to oversee the rescue operation, Russian news agencies said.
The mine, at Novokuznetsk, was opened in 2002 and had modern equipment, regional officials said.
Russia's coal mines are largely unprofitable and many have not invested in new safety equipment since the collapse of the Soviet Union in 1991.
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