Another 12 people were wounded in the attack with some reported to be in critical condition.
The Turkish authorities did not immediately comment, but did not rule out the attack being the work of rebels from the Kurdistan Workers Party (PKK).
However, the local Dogan news agency said the incident occurred due to a blood feud.
The PKK has been fighting for an autonomous ethnic Kurd state in southeast Turkey for nearly 25 years. The conflict has so far claimed over 40,000 lives.