Twenty-one coal miners have died attempting to rescue trapped workmates in northern Iran after an explosion Wednesday caused a mile-long tunnel to partially collapse, news agencies said. Tragically, the bodies are those of miners who went into the tunnel to try to save 32 trapped workmates who are still missing, the agencies reported.

The Zemestan Yort mine tunnel in Golestan province caved in when methane gas exploded underground as workers tried to jump-start a locomotive engine, according to initial reports. "Thirty-two miners have been trapped at the end of one of the shafts 1,300 metres deep into the mine," Golestan governor Hassan Sadeghlou said, quoted by state media.

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. "Some 600 metres (yards) of the tunnel has been cleared" in the mine, said Reza Bahrami, a mining industry official in Golestan.

Copyright Agence France-Presse, 2017