Twenty people were rescued from the mine in Soma in Manisa province but one later died in the hospital, town official Mehmet Bahattin Atci said.
There were reports around 300 miners remained trapped more than a mile below the surface and a mile-and-a-half from the mine’s exit.
Search and rescue operations were ongoing but senior local official, Mehmet Bahattin Atci, said thick smoke at the private mine was continuing to hamper rescue efforts.
Mr Atci said a power distribution unit had exploded, trapping up to 300 workers.
It was estimated around 580 workers were underground at the time of the blast, but that many had been able to escape.
Turkey’s energy minister Taner Yildiz confirmed a number of miners had died, but refused to confirm exactly how many had succumbed to smoke inhalation and burn injuries.
He told reporters that the fire at the mine was triggered by an electrical fault
The minister was travelling to the site of the incident to oversee the rescue operation.
He said: “It is a serious accident.
“Our priority is to reach our miner brothers … any figure we give could well be wrong.”
He also said that four separate rescue teams were currently working in the mine.
The energy minister added: “The fire creates a problem but oxygen is being pumped into the mine shafts that weren’t affected.”
Union officials said the explosion happened during a change of shifts, leading to uncertainty over the exact number of workers still inside. NTV television said the incident occurred more than a mile underground.
A witness told the TV station that ambulances were seen entering and leaving the area.
Footage showed dozens of fellow workers and family members gathering outside the hospital in Soma, which is about 155 miles south of Istanbul.
Mr Yildiz said rescuers were pumping fresh air into the mine and rescue teams from neighbouring regions were rushing to the area.
Tamer Kucukgencay, chairman of the regional labour union, 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.”
Turkish president Abdullah Gul has ordered the regional governor to deploy all resources to rescue the miners.
Soma MP Muzaffer Yurttas earlier told NTV 20 bodies had been retrieved and that at least another 20 workers were taken to hospital. But he said later that four people had been killed.
“They died of choking and burns,” he said.
Mining accidents are common in Turkey, which is plagued by poor safety conditions. Analysts say the safety record of Turkey’s coal mining industry lags that of most industrial nations.
Turkey’s worst mining disaster was a 1992 gas explosion that killed 270 workers near the Black Sea port of Zonguldak.
Fatal incidents since have included 13 miners being killed near Dursunbey in north-west Turkey in 2010, two months after a blast in Bursa killed 19.
A total of 17 people were also killed in the Dursunbey mine in 2006.