At least 295 people were killed and 350 others were injured when railway wagons carrying sulphur, petrol and fertiliser derailed and exploded in Iran.

Provincial officials in the northeastern city of Mashhad said dozens of wagons began rolling out of control for an unknown reason before coming off the tracks and catching fire.

The cargo blew up as fire fighters - watched by curious villagers - were attempting to douse the flames.

The blast happened near the town of Neyshabur in the north east of the country.