In addition to the dead, Andriy Bondareknko, the regional head of the country's emergency situation ministry, said three people were injured on Sunday by the blast at the Karl Marx mine in the region of Donetsk.

The mine, located in the town of Yenakiyevo, 595km southeast of the Ukrainian capital Kiev, had been closed several days before the accident due to safety violations.

A ministry statement said the explosion occurred about one kilometre underground at the Karl Marx pit in Donetsk region, at the heart of the coalfield.

According to Marina Nikitina, head of local branch of the Committee for the Protection of Labour, a work safety organisation, three women operating the elevator shaft were hospitalised with serious burns and at least one other person on the surface was injured.

Lyuda Bortok, a local journalist, told Al Jazeera that voices could be heard from the mine.

"Some people near the scene of the accident said they had heard the voices of some of the missing coming from the mine," she said.

The mine was closed down on Saturday due to safety violations and only a skeleton staff was working at the time of the blast, the emergency ministry said.

Gas explosions are a frequent occurrence in Ukraine's outdated mines, many of which date from the 19th century.

Three explosions at the Zasyadko mine in Donetsk late last year killed

106 men in two weeks.