At least 11 people died Wednesday when a fuel tanker collided with a bus in western Iran, state media reported.
The vehicles crashed shortly after midnight (1900 GMT Tuesday) in Sanandaj, the capital of Iran's Kurdistan province, around 400 kilometres (250 miles) west of Tehran, according to state television.
The IRNA news agency said four bus passengers and three passers-by were also injured in an "enormous explosion" following the collision.
Local authorities have declared three days of mourning in the province, it said.
While its roads are in generally good shape, Iran has a poor record on traffic safety, with accidents caused by reckless drivers killing thousands of people each year.