Four hours after an explosion killed at least eight people in Russia's largest coal mine, Raspadskaya, another blast rocked the West Siberian mine, a source in the mine's administration said on Sunday.
"The blast took place at about 1:00 a.m. Moscow time," the source said without elaborating.
The information is yet to be officially confirmed.
According to previous reports, a total of 66 miners were trapped underground by the first blast, and rescuers established contact with some of them.
Twenty four people sustained injuries.
An emergencies ministry officer earlier said the explosion occurred at 8:55 p.m. Moscow time (16:55 GMT). There were 359 people in the mine at the moment of the first blast, and 282 people, including those killed, were already taken to surface.
A local journalist, who is reporting from the scene, told RIA Novosti by phone that he also heard the second blast. He also said that the miners, who managed to escape, are currently leaving the building on their own.
"They are leaving the mine's building, feel well," Oleg Chmykhalov said.
He said the relatives of the injured have not arrived at the mine yet.
"There is quite a long way [from the mine] to Mezhdurechensk [where most miners live]. They [relatives] are probably on their way, or were not informed yet," the journalist said.
A spokeswoman for the regional investigation department said the cause of the blast is yet unknown.
"It definitely was a blast. We are now trying to establish if the explosion was caused by firedamp or by pulverized coal," Natalya Ananyeva said.
Russian energy ministry has set up a special group to deal with the aftermath of the explosion.
Russian emergencies minister Sergei Shoigu immediately informed Russian President Dmitry Medvedev about the accident and the ongoing rescue operation.
"Medvedev ordered the emergencies ministry head to report about the rescue efforts," and use every opportunity to rescue people, the Kremlin press service said.
A total of 12 rescue teams are currently involved in rescue efforts. Rescuers from neighboring regions have been put on alert and will arrive if necessary.
Russian Prime Minister Vladimir Putin discussed the accident with the region's governor, Aman Tuleyev.
A Russian deputy energy minister, Vladimir Azbukin, is to visit the mine later on Sunday.
This is not the first deadly accident in the mine, owned by a leading Russian coal producer, Raspadsky Coal. In 2008 the mine was closed for two weeks due to numerous safety violations.
In late January, a worker was killed when ceiling collapsed in the mine. On March 30, 2001, a methane blast killed four miners and injured six.
KEMEROVO, May 9 (RIA Novosti)