The Interfax news agency quoted Ukrainian civil defence sources as saying that four injured miners were rescued. The fate of the remaining miners was unclear.

The methane gas explosion occurred in the morning in the Karl Marx mine shaft in the Yenakiyevo area at a depth of around one thousand meters (3,300 feet).

Ukrainian coal mines are among the most dangerous in the world due to the lack of safety measures.

According to witnesses, the explosion was so powerful that it broke windows above ground. The impact also destroyed the subterranean air supply system.

Mine owners said the mine was lightly manned as it was closed Saturday due to safety considerations.

The Ukrainian government in the past months has closed dozens of mines due to the high number of fatal accidents.