It quoted a police official as saying that the driver of the bus, that was travelling to the capital Tehran from a city near the Caspian Sea, was driving at high speed and lost control of the vehicle.
The accident came a day after at least 30 people were injured when a truck driver crossed a railroad at high speed and crashed into a train in the north of Iran.
Iran has a good road network but accidents caused by reckless drivers kill thousands each year.
