Polish President Andrzej Duda has expressed pessimism about the fate of ten trapped miners.
"There is a high probability that there are dead people in the Zofiowka mine, but we still hope that we can get the surviving miners out," said the head of state, who personally came to the scene of the accident on Saturday evening, to the PAP news agency.
The mine management had previously informed that rescuers had been able to locate four of the ten missing people, but had not noticed any signs of life from them.
Details should first be communicated to the families and only later to the public.
Officials would not specifically say whether the four men were dead.
After a tremor in the southern Polish coal mine, ten miners were missing on Saturday morning.
Prime Minister Mateusz Morawiecki confirmed this on Facebook: “Another devastating news from Silesia – at 3.40 a.m. there was a powerful tremor in the Zofiowka coal mine in Jastrzebie-Zdroj.
A rescue operation is underway, unfortunately there is still no contact with ten miners,” wrote the national conservative politician.
He concluded his message with a prayer to Saint Barbara, the patron saint of miners.
Leaked methane makes rescue difficult
Mine management confirmed to the PAP news agency that 52 miners were in the danger zone at the time of the tremor.
42 of them were able to escape uninjured on their own.
The search for the other ten men is difficult because a large amount of methane has escaped and could endanger the rescuers.
Only on Wednesday there had been two methane gas explosions in another mine in Silesia belonging to the same company.
Five men were found dead, seven more buried.
The search for them was called off on Friday without result because it had become too dangerous for the rescuers themselves.