0408 GMT July 21, 2018
The bus bound for Tehran departed from the bus terminal of Sanandaj, capital of the western province of Kurdestan, a few minutes after midnight on Wednesday.
When the bus pulled over to take in more passengers, a fuel tanker struck it from behind, causing a huge explosion that burnt not only the bus and the truck, but also three other vehicles in the vicinity.
One of the two bus drivers who survived in the crash said that bus had stopped to pick up passengers when it was suddenly hit by the tanker.
An official with the fire department of Sanandaj said 13 people have been killed in the crash, including 12 bus passengers and the tanker driver.
Mehr News Agency reported early on Wednesday that the tanker was carrying tar.
The governor of Kurdestan Province has declared three days of public mourning, urging an immediate and detailed report on the cause of the incident.
A number of officials, including president and Parliament speaker, in separate messages condoled with the families of the victims.
President Hassan Rouhani ordered the province’s governor general to launch an investigation into the accident.
“The tragic and terrible accident in Sanandaj passenger terminal that left a number of our fellow Iranians in Kurdestan dead and injured caused great grief and sorrow”, the president said in his message.
Iran has a poor record on traffic safety, with such accidents killing thousands of people each year.