The explosion occurred outside the town of Azadshahr in Golestan province in the Zemestan Yurt mine, ILNA said.

"Unfortunately, all miners trapped in the wreckage lost their lives," Minister of Labor and Social Affairs Ali Rabiei told the press.

Shahin Fathi, Head of the Iran Red Crescent Search and Rescue Unit, said more than 40 miners had been trapped and six of them were rescued with injuries.