“I must say that our hopes about rescue efforts inside (the mine) are fading,” AFP quoted Taner Yildiz as saying on Wednesday.
The explosion at the mine has reportedly left at least 240 people dead and more than two hundred others trapped.
Yildiz said the death toll could increase.
“We are worried that human loss could increase,” he said, adding, “The problem is more serious than we thought. It is developing into an accident with the highest worker death toll Turkey has seen so far.”
Yildiz further noted that fires and the risk of toxic carbon monoxide are hampering rescue efforts.
He had said earlier in the day that 80 miners had also been injured in the explosion and ensuing fire in the mine and noted that 787 workers had been underground at the time of the blast.
On Wednesday, the office of Turkish Prime Minister Recep Tayyip Erdogan issued a statement, announcing three days of national mourning.
“Three days of national mourning have been declared as of May 13 due to the mine disaster in Soma” in western Turkey, the statement said.
Lignite coal mining is a major industry in Turkey’s Soma. A similar incident in 1992, marked the country’s worst mining disaster in which 270 miners were killed near Zonguldak, on the Black Sea.