By Becky Bratu, Staff Writer, NBC News
Eighteen miners are trapped underground in a Polish copper mine after an earthquake caused a cave-in, according to Reuters.
Dariusz Wyborski, a spokesman for mine operator KGHM, told newspaper Gazeta Wyborcza the situation is serious and the miners' lives are at risk.
"The newest information is that 18 miners are trapped, four people have walked out earlier on their own," KGHM said in a statement after earlier news mentioned 17 workers trapped.
Reuters reported that the miners are trapped about 600 yards below ground at the Rudna mine, about 249 miles southwest of the Polish capital, and there has been no contact with them for two hours.
"There was a quake in the Rudna mine," Wyborski said, according to Reuters. "The rescue operation is difficult because huge amounts of rocks have to be removed."
Four injured miners were able to come out of the mine on their own, according to Gazeta Wyborcza. Officials have no information on the remaining miners because the tremor cut communication lines, the company said.
Rescuers are unable to get in, as debris blocks the way.
The mine, which has been in operation since 1974, is in the Silesia region, near Poland's borders with Germany and the Czech Republic. The operator, KGHM, is Europe's second-biggest copper producer.
Poland has large numbers of mines, mostly in the heavily industrialized Silesia region. In 2006, a gas explosion at a coal mine in the region killed 23 miners.
Reuters contributed to this report.