Dozens of people lost their lives and many others sustained injuries after a huge explosion caused by a gas leak at a coal mine in the eastern Iranian province of South Khorasan.
According to local media, a leak of methane gas led to the blast in two blocks of Madanjoo mine in the vicinity of Tabas on Saturday night, leaving at least 31 people dead and many others injured.
The death toll is likely to mount as many continue to be in critical condition, according to sources.
"There was an explosion and unfortunately 69 people were working in the B and C blocks of Madanjoo mine. In block C there were 22 people and in block B there were 47 people," said Javad Ghenaatzadeh, South Khorasan governor.
State TV broadcast footage of ambulances and helicopters arriving at the scene of the incident to transport the injured to hospital.
Online footage carried by IRNA showed the bodies of some of the victims, wearing their work uniforms and being carried out of the site on mining carts.
Iran's Red Crescent Society said search and rescue operations were underway in the mine but "gas accumulation in the mine" has made the search operations difficult.
Iranian President Masoud Pezeshkian expressed condolences to the victims' families and ordered that all efforts be made to rescue those trapped and to help their families.
He also said an investigation into the incident had begun.
"Unfortunately, we learned that an incident 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.
Judiciary Chief Gholamhossein Mohseni-Ejei instructed the provincial governor in South Khorasan to expedite emergency services to the injured and said "the negligence and fault of the relevant agents will be legally dealt with" later.
Vice President Mohammad Reza Aref also spoke with cabinet members to ensure "emergency follow-up" and support for the victims and their families.
Authorities in South Khorasan announced three days of mourning across the eastern province following the tragic incident.