The blast occurred at 3.39 am (0039 GMT) at a depth of 300 meters, they said in a statement.
The mine is in the small town of Kirovske, 90 km (56 miles) north of the regional capital Donetsk and 40 km (25 miles) from Slaviansk, in the Donbass mining region where pro-Russian separatists have taken up arms in some areas. Russia's Gazprom: Russian natural gas exporter Gazprom will halt supplies to Ukraine if it fails to pay off $1.95 billion of its gas debts by Monday, chief executive Alexei Miller said on Thursday. "If Ukraine pays for no (gas) volumes at all, it means that ... gas shipments to Ukraine will be zero," he said in televised comments. Miller also said Bulgaria had not notified Gazprom of any suspension of work on construction of the South Stream pipeline to deliver Russian gas to Europe and that the project was still under way. REUTERS