At least 51 workers were killed in a coal mine explosion in northeastern Iran, according to local media on Sunday.
The explosion was caused by a rapid release of methane and carbon monoxide Saturday night in two blocks in the mine in Tabas in Khorasan province, the state news agency IRNA reported.
Local authorities said that around 70 workers were at the mine at the time of the explosion.
Iranian authorities cited difficulties in carrying out a rapid rescue operation due to underground conditions.
Iranian President Masoud Pezeshkian has ordered an investigation into the explosion.
The mine explosion adds to a troubling history of mining accidents in Iran, where safety regulations are often overlooked.