A blast caused by a gas leak at an Iranian coal mine has killed at least 51 people, state media said Sunday, in one of the country’s deadliest work accidents in years. “The number of dead workers increased to 51” in the explosion at the Tabas mine in eastern Iran, the official news agency , revising an earlier death toll of 30. It added that 20 other people were injured. The explosion occurred at around 9pm (1730 GMT) on Saturday, when around 70 workers were present at the site in South Khorasan province, said. According to the report, a leak of methane gas led to the blast in two blocks of the mine, which is owned by private Iranian firm Madanjoo. State TV broadcast footage of ambulances and helicopters arriving at Tabas to transport the injured to hospital. Online footage carried by showed bodies of some of the victims, wearing their work uniform, carried out of the site on mining carts. South Khorasan governor Javad Ghenaat told state TV that rescue teams were working to recover the remaining bodies. Iran’s President Masoud Pezeshkian, in remarks carried state TV before departing for the UN General Assembly in New York, offered his condolences to the families of the victims and ordered a probe into the deadly incident. “Unfortunately, we learned that an accident occurred in one of the coal mines in Tabas and a number of our compatriots lost their lives. I offer my condolences to their respected families,” Pezeshkian said. His first vice president, Mohammad Reza Aref, spoke with cabinet members to ensure “emergency follow-up” and support for the victims and their families, said. Iran’s Red Crescent said search and rescue operations were underway in the mine, where some workers remained trapped. According to , they were about 250 metres below the surface, cut off from rescuers by chambers that had filled up with concentrated methane gas. “Gas accumulation in the mine” has made the search operations difficult, local prosecutor Ali Nesaei was quoted by as saying. “Currently, the priority is to provide aid to the injured and pull people from under the rubble,” Nesaei said. He added that “the negligence and fault of the relevant agents will be dealt with” later on. Last year, an explosion at a coal mine in the northern city of Damghan killed six people, also likely the result of methane leak according to local media. In May 2021, two miners died in a collapse at the same site, local media reported at the time. A blast in 2017 killed 43 miners in Azad Shahr city in northern Iran, triggering anger toward Iranian authorities. Mineral-rich Iran has around 1.5 billion tons of proven coal reserves, according to state media. The Tabas mine covers an area of more than 30,000 square kilometres and holds mass reserves of coking and thermal coal, according to . It is “considered the richest and largest coal area in Iran,” said.