An explosion at a mine in northern Iran on Wednesday left at least 26 workers trapped in a mile-long tunnel filled with gas that hampered rescue efforts, media reports said.
The coal mine in Golestan province collapsed when methane gas exploded underground as workers tried to jump-start a locomotive engine, according to the reports.
Two bodies were recovered from the Zemestan Yort mine, Fars news agency cited the Red Crescent as saying.
The rescue operation was going slowly as tunnels were filled with poisonous gases and miners were stuck at the far end of a 1,000-metre (yard) shaft in a mine that is around two kilometres (1.2 miles) long.
Emergency workers had only reached a depth of 800 metres into the mine, Tasnim news agency cited Hossein Ahmadi, the director of the province's Red Crescent, as saying.
Authorities were planning to dig a side tunnel to access the trapped workers in the mine near Azadshahr, one official there said.
Initial reports put the number of those trapped in the mine at 80, but that figure was later reduced significantly.
"According to the person in charge of the mine who has counted the workers, it is estimated that there are 26 miners stuck underground," state broadcaster website IRIB quoted a crisis management official as saying.
Another official said the priority was to remove the monoxide gas concentrated in the tunnel, as there was still the risk of another explosion.
The teams were hoping to speed up work as an air-pumping machine had arrived at the site.
Some 30 miners were treated in various hospitals for gas poisoning and injuries, state news agency IRNA reported.
There was no information on the condition of those trapped.
The workers sent to hospital were among those who had rushed from outside to help the victims after the blast.
Iran's President Hassan Rouhani has sent Minister of Labour and Welfare Ali Rabii to the mine in order to oversee the rescue operations and treatment of victims, IRNA reported.
First Vice President Eshaq Jahangiri expressed condolences to the families of the victims and tasked Minister of Mining and Industry Mohammad Reza Nematzadeh with investigating the cause of the accident.
The issue is particularly sensitive two weeks ahead of a presidential vote when Rouhani hopes to win re-election.
Conservative candidates have accused the government of failing to care for the poor.
The mine has 500 workers and the explosion happened during a change of shift, state media said.
© 2017 AFP