At least 11 miners were killed and 45 others injured in a coal mine accident in the Russian city of Kemerovo as a rescue operation continues to save several trapped miners, authorities announced on Thursday.

According to the governor's office of Kemerovo Oblast, 285 miners were in a shaft when the ignition of coal dust caused heavy smoke at a depth of 250 meters (820 feet) that killed 11 people.

During a rescue operation, 239 people were evacuated from the mine, 45 of them hospitalized.

Kemerovo Oblast is one of Russia's most important industrial regions in southwestern Siberia, with some of the world's largest deposits of coal.

Heavy smoke is hindering the rescue efforts underway to save the miners who are still trapped in the shaft.

The Kemerovo Oblast prosecutor's office has started an investigation into the accident.

Russian President Vladimir Putin offered his condolences to the relatives of those killed and hoped for the early evacuation of those still underground.