Polish officials have said they fear the worst for 15 miners trapped in a deep coal mine after an explosion that jkilled another eight of their colleagues.

Rescuers worked into the early of hours of Wednesday in their attempts to free the men in the mine beneath the town of Ruda Slaska, about 300km southwest of the capital Warsaw.

They tried to pump air into one of the mine's tunnels in a bid to cope with conditions that were described as "hell".

A spokesman for the state-run Kompania Weglowa coal group, Zbigniew Madej, said it could take several hours to ventilate the underground area.

He said it was impossible to say if the rescuers would reach the 15 in time.

"We fear the worst," he said. "The conditions down there (for rescuers) are extreme. It is hell."

The miners were caught in a massive explosion on Tuesday afternoon as the men, aged between 21 and 59, were retrieving equipment from a section of the Halemba mine where it had been abandoned because of dangerously-high gas concentrations.

Officials said the chief obstacles to rescue efforts were deposits of methane gas, lack of air and temperatures of up to 40C (104F).

Grzegorz Pawlaszek, head of the state-owned Coal Company, said rescue teams had recovered seven bodies from the scene of the blast.

Another body had been located but could not be reached because the high concentration of methane gas meant there was the risk of another explosion.

Madej said: "The rescuers have reached the eighth man but were forced to withdraw due to the threat the methane will explode again.

"Ventilating the shaft may last up to 8-9 hours. It is difficult to say what barriers we will meet (after that)."

Jaroslaw Kaczynski, the Polish prime Minister, flew to the mine to watch rescue efforts and promised help for the families of the miners.

Friends and relatives of the trapped men gathered at the mine as officials read out their names.

"Me and my son, we are waiting for my husband," said Barbara Luczakiewicz. "We hope he will get out of there. I am very scared but I haven't lost hope."

Andrzej Labus, a miner who was in a nearby shaft when the disaster occurred, said: "There was a huge blast and suddenly everything turned black. We were terribly scared."

The Halemba mine is one of the oldest in Poland and has been in operation since 1957.

PHOTO CAPTION

Miners gather outside the Halemba mine the day after an explosion killed at least 8 people in Ruda Slaska near Katowice, southern Poland, November 22, 2006. (Reuters)