Authorities said initial indications were that the blast was caused by firedamp, a term referring to methane in coal mines.

Eleven of the 58 rescued miners are still undergoing treatment in hospitals,  but it was not clear how many people were still trapped due to the blast that occurred as 110 people were working.

In 2014, 301 workers were killed in Turkey's worst-ever mining disaster in the western town of Soma, 350 km south of Istanbul.

Source/Photo REUTERS/Cagla Gurdogan