Hundreds are trapped inside a mine located in Soma in western Turkey.
An explosion and fire in a Turkish coal mine killed at least 200 people and the death toll could rise with hundreds more still trapped, the country's energy minister said.
Speaking to reporters at the scene of the Tuesday disaster, Energy Minister Taner Yildiz said 787 workers were inside the mine when the blast hit a power unit and 363 of them had been rescued so far.
"Regarding the rescue operation, I can say that our hopes are diminishing," Yildiz said on Wednesday morning. At least 80 people were injured, he said.
Yildiz said most of the deaths were the result of carbon monoxide poisoning.
The blast at the mine in Soma, around 75 miles northeast of the Aegean coastal city of Izmir, happened during a change in shifts, leading to uncertainty over the exact number of workers still inside, officials said.
"They are pumping oxygen into the mine, but the fire is still burning. They say it is an electrical fault but it could be that coal is burning as well," Tamer Kucukgencay, chairman of the regional labor union, told Reuters.
Television footage showed dozens of fellow workers and family members gathering outside the hospital in Soma.
Nurettin Akcul, head of the Turkish Mineworkers' Union, said the blast happened around 1.2 miles below ground.
Yildiz confirmed that a fire had been triggered by an electrical fault.
The initial death toll earlier on Tuesday had been much lower, first estimated at four, and then 15.
Earlier in the day, Mehmet Bahattin Atci, mayor of Soma, said 200 to 300 workers were still inside following the explosion. The head of the local fire service also told Turkish television that around 300 workers were still trapped.
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 270 workers near the Black Sea port of Zonguldak.
Al Jazeera and wire services