A blast at a coal mine in the eastern Ukrainian city of Donetsk killed more than 30 people, a local official said on Wednesday, March 4, with dozens more miners who were underground at the time unaccounted for, Reuters reported.

Local officials said about 70 people were working in the mine when the explosion happened. One worker, leaving the mine in dirty overalls, said he had heard that 45 people were still trapped underground, though there was no immediate confirmation of this figure.

"According to preliminary information, more than 30 people were killed. Rescue workers have not yet come to the place of the explosion, they are removing the poisonous gas and then will go down," said Vladimir Tsymbalenko, the head of the local mining safety service.

The cause of the blast in the Zasyadko coal mine was not immediately clear. An explosion at Zasyadko in 2007 killed 106 people.