Seven miners were injured early on Sunday in an explosion at a coal mine in western Siberia, a local source told RIA Novosti.
The incident occurred at the Gramoteyevskaya coal mine near the town of Belovo in the Kemerovo region at 04.56 Moscow time (00:56 GMT).
"The latest reports indicate that seven miners received injuries of varying severity and were hospitalized," the source said.
Russia's Emergencies Ministry earlier said four miners were injured in the blast, and a total of 55 workers were rescued.
The explosion did not start a fire or trigger a ceiling collapse, the ministry reported.
High concentration of methane remains the major cause of deadly incidents at Russian coal mines.
Two powerful methane blasts at the Raspadskaya mine near the west-Siberian town of Mezhdurechensk in May, 2010, killed 91 people, including rescue workers. Only 80 bodies have been uncovered from the mine.
Kemerovo is part of Russia's major coal-producing Kuzbass region.