An explosion of methane gas accumulations killed at least 21 people in the Ulyanovskaya mine in Kemerovo region (southwestern Siberia) at about 11:16 a.m. Moscow time (0816 GMT), the Russian Ministry of Emergency Situations announced.

Within the mine there were about 186 when the blast occured. Only 86 of them were taken out by the time of the announcement. Twenty-one bodies had been pulled from the mine, Interfax quoted regional officials as saying at 1600 Moscow time (1300 GMT).

"The rescue operation is still under way," a regional spokesman told Reuters.

"It was a methane gas explosion," a spokeswoman at Russia's emergency ministry told AFP news agency.

"The latest information is that there were 168 miners inside at the time of the blast," she said.

"We're talking about a very large accident," an official at Russia's Federal Service for Ecological, Technological and Nuclear Control told Interfax.

The mine, 1,850 miles east of Moscow, is owned by OAO Yuzhkuzbassugol, Valery Korchagin, a spokesman for the Kemerovo region's emergency services, said by phone to Bloomberg.