At least seven people were killed after a tractor carrying nut workers overturned in western Sakarya province, said a security source on Friday.
The source, who spoke on condition of anonymity due to restrictions on speaking to media, said 10 others were also injured in the accident.
The cause of the accident is unknown. Many ambulances were dispatched to the scene.
The seasonal workers were said to be from the southeastern province of Diyarbakir.