At least 35 miners were killed following an explosion at the Zemestanyurt coal mine in the Golestan province of northeastern Iran on Wednesday, according to news agencies in the country. The mine is located 14 kilometers (9 miles) from Azadshahr.

The explosion occurred at 12:45 p.m. local time (0945 UTC) according to provincial spokesman Ali Yazerloo.  Iranian state news agency IRNA said 21 bodies were found after nightfall. The deceased were trying to save 32 workers who were still trapped in the tunnel.

"Thirty-two miners have been trapped at the end of one of the shafts 1,300 meters (0.8 miles) deep into the mine," said Golestan governor Hassan Sadeghlou according to state media.

An unidentified miner told AP that he carried two co-workers out of the mine.

The rescue mission was not going well as rescue tunnels filled with poisonous gas. An official said the current priority was to remove potentially explosive gas that has concentrated in the tunnel the workers are trapped in, as there was a risk for another explosion. Rescue teams at the mine are hoping to speed up the process as an air-pumping machine arrived at the site.

The provincial director general of disaster management, Sadegh Ali Moghadam, told IRNA there was a "possibility of the death toll rising." There is no information on the condition of those trapped in the mine.

Officials blamed the explosion on explosive gas building up in the mine. Previous disasters in Iran's coal mines have been blamed on low safety standards and inadequate emergency services. Mining incidents in Iran killed 11 workers in 2013 and 20 workers in 2009.

kbd/bw (AFP, AP)