At least 157 miners have been killed and hundreds remain trapped underground after an explosion and fire in a coal mine in the western Turkish province of Manisa on Tuesday, the mayor said.

“According to unofficial data, the death toll has reached 157 and 75 injured,” Manisa mayor Cengiz Ergun told CNN Turk television. Official disaster response unit AFAD earlier put the death toll at 17.

Authorities say the disaster followed an explosion and fire caused by a power distribution center.

A government official told The Associated Press that the death toll was expected to rise further.

Turkish Energy Minister Taner Yildiz said the situation was “worrisome” and rescue efforts would last until the morning.

It was not immediately clear how many more miners were still trapped in the coal mine in the town of Soma, some 250 kilometers (155 miles) south of Istanbul.

Television footage showed people cheering and applauding as some trapped workers emerged out of the mine, helped by rescuers, their faces and hard-hats covered in soot. One wiped away tears on his jacket, another smiled, waved and flashed a “thumbs up” sign at onlookers.

The accident occurred during a shift change so the exact number of trapped workers was not known. Authorities had said the blast left between 200 to 300 miners underground but the disaster agency later gave the number as “more than 200 workers.”

There was no information on the condition of those trapped. But the disaster management agency said authorities were preparing for the possibility that the death toll could jump dramatically, making arrangements to set up a cold storage facility to hold the corpses of miners recovered from the site

Turkish Prime Minister Recep Tayyip Erdogan, who had cancelled a trip to Albania, was headed for the disaster site, Turkish media reported.

The former head of the miners’s union in Turkey, Çetin Uygur, said the incident was “truly a workplace murder of the highest degree,” as quoted in the newspaper.

Mining accidents are common in Turkey, which is plagued by poor safety conditions.

Turkey’s worst mining disaster was a 1992 gas explosion that killed 263 workers near the Black Sea port of Zonguldak.