(Reuters) - Dozens of miners were trapped underground and feared dead after a blast on Wednesday at a coal mine in the eastern Ukrainian rebel stronghold of Donetsk, with rescuers saying the chance of finding many survivors was slim.

Mine officials said the explosion was not linked to fighting at the nearby frontline in the war between Moscow-backed rebels and Ukraine government forces. Kiev accused the separatists of holding up the rescue effort by restricting access.

Outside the gates of the Zasyadko mine, about 30 relatives clamoured for information about any survivors. A miner injured in the blast mingled with the crowd, his face covered in scratches and one arm hanging motionless by his side, the result of a broken collarbone.

The miner, Sergei Baldayev, said five bodies had so far been retrieved from the area of the blast, in a shaft deep underground.

The sister of one miner who was in the pit at the time of the explosion, Alexei Novoselsky, stood in tears.

"Tell me, are there survivors? Why are you concealing the truth," she said as a local rescue services employee tried to calm her.

Donetsk has been the scene of heavy fighting between Moscow-backed separatist rebels, who control the region, and forces loyal to the government in Kiev. A ceasefire has sharply reduced the violence in the past week.

The neighbourhood around the mine has come under artillery fire, with fragments from Grad rockets visible on surrounding roads, but mine officials said the explosion was unrelated to the fighting and most likely caused by gas.

In Kiev, Ukrainian Prime Minister Arseny Yatseniuk said rescue workers had been dispatched by the central authorities, "but the Russian terrorists did not let them reach the scene of the accident," he said, using a term commonly used by Kiev to describe the separatists.

Figures given by medical workers at the scene, miners and a mine official speaking on condition of anonymity pointed to there being about 50 miners still underground.

Earlier on Tuesday, some officials had said more than 30 people were killed in the early morning blast, although later officials would not confirm that figure. Rescue services were working to reach the epicentre of the blast, in a shaft deep underground, they said.

Asked what were the chances of trapped miners surviving, a medical worker said: "It's getting smaller and smaller all the time, because of the methane, the hot air, burns to the airways."

She said two buses had been brought to the mine in preparation for carrying away the bodies of the dead.


The mine has a history of fatal accidents in the 57 years it has been operating. An explosion at Zasyadko in 2007 killed 106 people. A cemetery next to the pit holds the graves of many miners killed in the past.

"When there's an accident, we bury them all here," said the head of security at the shaft where Tuesday's blast happened, who did not give his name. "Coal is a costly business."

A welder at the mine, who gave his name as Oleg, said outside the entrance: "I've been down the pit for 23 years, and this is the fourth explosion that I can recall. If they didn't get them out straight away, then later they will only retrieve bodies. An explosion is a terrible thing."

The Zasyadko coal mine produced 1.4 million tonnes of coal in 2013. The mine is in the centre of a Donbass region which is Ukraine's industrial and coal-producing heartland.

Ukrainian coal production fell 22 percent in 2014 to 65 million tonnes as the conflict disrupted mining operations in the region, leading to some shortages of coal at power plants.