Turkey mine explosion
An injured miner is carried to an ambulance in Soma, a district in Turkey's western province of Manisa May 13, 2014. Reuters

At least 166 miners have been killed in a coal mine explosion in western Turkey. Rescuers are trying to save more than 200 trapped underground.

Turkey's worst mine disaster in at least two decades was caused by an electrical fault in a mine in Soma, in Manisa province, around 250 kilometres from Istanbul.

Energy Minister Taner Yildiz, who confirmed the death toll, also said 787 people were inside the mine when the explosion happened. He said as many as 363 workers have been rescued.

According to the provincial Natural Disaster and Emergency Coordination Directorate, 200 workers are still trapped inside the mine.

Rescue personnel are pumping oxygen into the mine shaft to limit fatalities, Reuters reported. More than 100 rescue workers, dozens of ambulances and other rescue equipment were at the scene of the accident.

The dead were the victims of carbon monoxide poisoning, and authorities have said rescue efforts were hampered by the fact that the mine was not fully cleared of gas.

A power outage that followed the explosion crippled the mine's safety systems and hundreds were trapped inside as elevators failed to work.

Cengiz Ergun, the mayor of the province Manisa where the mine is located, confirmed scores of bodies have been retrieved from the mine.

However, the mine's premises and the hospitals witnessed chaotic scenes as thousands of family members of the miners clamoured for information, Reuters said.

Prime Minister Tayyip Erdogan cancelled a foreign travel and would rush to the scene of the disaster, his office said. "Rescue efforts for our brothers in the mine are ongoing ... God willing, in the coming hours, I hope to receive uplifting news," Erdogan said as news of the explosion broke.

Turkish authorities and trade union leaders have expressed fears that the accident could be the biggest mining disaster in the country's history.

Turkey's worst mining accident happened in 1992, when 263 workers were killed in a mine explosion in the Zonguldak province.

"Time is working against us. We fear that the numbers could rise further," energy minister told HaberTurk television. "We have to finish this [rescue operation] by dawn. I have to say that our pain, our trouble could increase."