Story highlights Crash happened in Semnan province in northern Iran, east of TehranIt's not clear what caused the crashTehran, Iran (CNN) Two trains collided in northern Iran on Friday morning, killing at least 31 people and injuring dozens of others, Iran's official Islamic Republic News Agency reported. Flames blazed and black smoke poured from at least one train car in the province of Semnan, east of Tehran, video distributed by Reuters and official Iranian news channel IRINN showed. At least one of the trains had passengers, some of whom were burned by the fire, IRNA reported, citing Ali Yahyaei of the Red Crescent Society. Frosty conditions slowed firefighters' access to the scene, IRNA reported. Information on what led to the collision wasn't immediately available.

Source: CNN November 25, 2016 13:03 UTC