Ukraine's Mining Inspectorate said the dead men were maintenance workers attempting to isolate the site of two previous explosions from the rest of the mine.
There were reported to be 231 miners underground at the moment of the blast.
On November 18, a blast at the Zasyadko mine in the Donetsk Region, the heart of the country's coal industry, caused a fire to rage through the mine. A total of 101 miners died.
On December 1, a second explosion ripped through the mine injuring more than 40 people. Following the second blast, a government commission decided to seal off the troubled area of the mine.