The governor of the Kemerovo region, Sergei Tsivilev, on Thursday announced the death of nine miners after a serious accident in a Russian coal mine in Siberia.
Tsivilev said that 49 people were still underground and that there was no communication with them.
The TASS news agency reported that 11 people had died in the accident as the exact death toll is still unclear.
A total of 237 workers have been rescued from the Liztvyazhnaya mine and more than 40 of them had to be treated in hospitals.
The reason for the explosion was initially unknown and the condition of the miners still underground was also unclear.
According to reports, the mine tunnels were heavily filled with smoke.
The explosion is said to have occurred at a depth of 250 metres.
Working in coal mines in Russia is considered extremely dangerous due to violations of elementary safety regulations as serious accidents repeatedly occur, often because of methane gas explosions.
The highly flammable gas is released during mining operations and accumulates in the shafts if ventilation is poor.