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.

'Voices heard'

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Gas explosions are a frequent occurrence in Ukraine's outdated mines, many of which date from the 19th century.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