At least 21 miners have been killed and 69 injured in an explosion in northern Iran, according to state media.
Rescue vehicles raced to the coal mine near Azadshahr, Golestan Province, with officials blaming a build up of gas for the blast.
Iranian state media reported that the explosion may have been triggered when workers at the Zemetsanyurt mine tried to jump start a locomotive engine.
Earlier, Sadeq Ali Moghadam, head of Golestan provincial emergency management department, said that 40 to 50 people were thought to be trapped inside the mine.
The explosion is understood to have taken place as workers were changing their shifts at the mine.
Images from the scene showed apparently dazed miners, covered in coal dust, being helped clear by onlookers.
More than 500 people are employed at the mine, which is nine miles from Azadshahr, close to the Caspian Sea and the border with Turkmenistan.