"Twenty workers were killed and around 30 were wounded in the accident. They died of choking and burns," Muzaffer Yurttas, a member of the ruling Justice and Development Party (AKP), told local TV station NTV.
Fire officials were desperately trying to pump clean air into the mine shaft for those who remain trapped some two kilometres below the surface and four kilometres from the entrance.
The mine collapse in Soma district was caused by an explosion following an electric fault, a regional governor told NTV.
"I don't want to give any numbers. We first have to reach our workers underground," Energy Minister Taner Yildiz told journalists before heading to Manisa.
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"Four separate rescue teams are currently working in the mine. The fire is creating a problem but oxygen is being pumped into the mine shafts that weren't affected."
Temel Korkmaz, head of the town's fire department, said an initial rescue team was able to enter part of the mine to rescue 30 wounded, who were taken to a nearby hospital.