Officials have launched an investigation to determine what happened.
At least eight people have been killed and 20 others have been injured in a coal mine accident in central Serbia.
According to Euronews Serbia, part of the mine pit collapsed on Friday morning, releasing methane gas and trapping the miners.
At least 49 workers were in the mine at the time of the accident, officials said. An investigation is underway to determine what happened.
“Inspectors, police and all relevant authorities are at the scene, doing what is necessary to determine the cause of this tragedy,” said Serbia mining and energy minister Zorana Mihailovic.
Mihailovic visited the site on Friday and expressed condolences to the families of the victims, promising state help.
Doctors in nearby Aleksinac, where injured miners have been brought, said most of their injuries are not serious.
Drago Milinkovic, the Soko coal mine manager, has also 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 told reporters.
“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.”
The Soko mine, about 200 kilometres southeast of Belgrade, has had several serious accidents since it started operating in the early 1900s.
Another accident in the mine in 1998 killed 29 miners, while 91 people were killed in a fire caused by human error at a mine in the Aleksinac region in 1989.