Ferit Basar, the mayor of the small town of Yukari Salat near the crash site, said the accident occurred amid heavy fog Wednesday in Diyarbakir's Bismil district on a stretch of road reduced to a single lane because of roadwork, Today's Zaman reported.
Fog, which had reduced visibility to about 16 feet, was likely a contributing factor in the accident between the mid-sized passenger bus and the truck, which was carrying bricks, Basar said.
The injured, many of them in serious condition, were taken to Bismil State Hospital, DiyarbakirGov. Mustafa Toprak said.
The Cihan news agency reported most of the bus passengers were from Siirt, and many of them were reportedly students.
Siirt residents gathered Wednesday afternoon at the city's Cumhuriyet Square to commemorate the victims.