At least 28 Afghan nationals have been killed in a crash in Iran, according to the country's Ilna news agency.
Another 21 people were said to have been injured in the collision.
Two vans crashed into each other near the town of Khash, in the south-eastern Sistan and Baluchistan province, the Associated Press reported.
The area is commonly used by traffickers transporting migrants across the Afghan border - often in desperate, cramped conditions.
Iran is one of the deadliest countries in the world for road traffic accidents, according to the World Health Organization.
In May this year, eight people were killed when a bus carrying 44 people overturned on the Qom-Tehran highway - reportedly because the driver fell asleep at the wheel.