At least six Turkish soldiers and six Kurdistan Workers' Party (PKK) militants have been killed in heavy fighting in the south-east of the country, the army said Friday.
Two pilots also died after a military helicopter involved in the fighting crashed, although the cause was probably a technical defect, the army added.
Eight soldiers were wounded in the clashes, which broke out early on Friday near a military base in Cukurca by the Iraqi border. Turkish ground forces were supported by F-16 fighter jets, attack helicopters and drones.
Turkish President Recep Tayyip Erdogan said the fight against terrorism will "continue with determination."
"No fighting, no ambush is able to keep us from defending the unity, solidarity and territorial integrity of Turkey," he said in a statement.
The PKK has been fighting for decades for self-determination for the Kurds in Turkey. The conflict escalated last year after a ceasefire was breached, and Turkish forces have been mounting large scale operations against the PKK for months.
On Thursday, four PKK fighters were killed in an explosion near the Kurdish city of Diyarbakir. The Turkish Interior Ministry said the blast occurred when militants were loading explosives onto a stolen vehicle.
At least 22 people were injured in the explosion, state news agency Anadolu reported. Television pictures showed a huge crater left behind by the blast.
The incident came just hours after an apparent car bomb attack targeted security forces in Istanbul. Five soldiers and three civilians were injured.
Police have arrested eight PKK suspects in the city over the car bombing, one of whom is alleged to have parked the vehicle, Anadolu reported on Friday.