Hundreds of people gathered outside the mine and the hospital in Soma seeking news of their loved ones. NTV television said people broke into applause as rescued workers arrived in ambulances. Interviewed by Dogan news agency, some complained about the lack of information from state and company officials about the situation of the trapped workers.
Police set up fences and stood guard around Soma state hospital to keep the crowds away.
SOMA Komur Isletmeleri A.S., which owns the mine, confirmed that a number of its workers were killed but would not give a specific figure. It said the accident occurred despite the "highest safety measures and constant controls" and added that an investigation was being launched.
"Our main priority is to get our workers out so that they may be reunited with their loved ones," the company said in a statement.
Mining accidents are common in Turkey, which is plagued by poor safety conditions.
Turkey's worst mining disaster was a 1992 gas explosion that killed 263 workers near the Black Sea port of Zonguldak.