Rescue teams sent to the area were unable to immediately enter the mine due to high concentrations of methane gas, and seven workers were treated in hospital for gas poisoning.

"The rescuers are running into difficulty because the accident area is very narrow and has suffered major damage," Dincer said.

He added it would take the teams until late Friday to retrieve all the bodies.

Mining accidents are common in Turkey, with safety violations and outdated equipment often contributing factors.

The worst disaster, at Zonguldak in 1992, killed 263 workers.

According to broadcaster CNN Turk, some 3,700 miners have been killed in work-related accidents since 1941.