CNN Turk broadcast video of a badly damaged bus surrounded by debris and other damaged vehicles under a pedestrian overpass in the area of Yuregir in Adana.
The sources said ambulances took the wounded to hospitals in the area. Armed police sealed off the area and were examining the scene.
It was not clear who might be behind the attack.
Adana Governor Mahmut Demirtas was cited by state-owned Anadolu news agency as saying initial information indicated the wounded were not seriously hurt.