At least 18 people have been killed and 15 others left wounded after a bus overturned in the western Iranian province of Kermanshah, PRESS TV reported.
The accident occurred on Sunday afternoon due to "the recklessness and inability of the driver to control the bus" on a road near the city of Sar Pol-e Zahab, IRIB reported.
Sar Pol-e Zahab Governor Mirza Morad Peiro said that the injured were shifted to nearby hospitals.
Forty-two passengers were on board the bus, the report says.
Iran is believed to have one of the highest road accident rates in the world.
According to a member of the Parliament (Majlis) Commission on Social Affairs, Alireza Zamani, road accidents leave 20,000 people dead and 200,000 injured every year in Iran.
The toll is blamed on unsafe vehicles, disregard for traffic rules and sometimes inadequate emergency services.