BELGRADE, Serbia (AP) -- An accident in a mine in central Serbia killed eight people and wounded 18 Friday, authorities said.
The accident in the Soko coal mine happened shortly after 4 a.m. (0200GMT). Officials said an investigation is underway to determine exactly what happened.
"Inspectors, police and all relevant authorities are at the scene, doing what is necessary to determine the cause of this tragedy," said the Mining and Energy Minister Zorana Mihailovic.
MIhailovic visited the site on Friday and expressed condolences to the families of the victims, promising state help.
The state RTS television and other local media said the accident happened when part of the mine pit collapsed, releasing the methane gas inside and trapping the miners.
Drago Milinkovic, the Soko coal mine manager, said initial information suggested a "sudden release of methane" gas into the mining area.
"Soko coal mine is a dangerous coal mine, dangerous from the aspect of methane," he said. "Security measures are at the highest level in the coal mine, but this time there was a sudden release of methane and simply the monitoring and the equipment that were in place did not help."
Doctors in nearby Aleksinac, where injured miners have been brought, said their injuries mostly are not serious.
The Soko mine, about 200 kilometers (125 miles) southeast of Belgrade, has had several serious accidents since it started operating in the early 1900s. An accident in the mine in 1998 killed 29 miners.