More than 100 Kurdistan Workers Party (PKK) militants were either killed or wounded in clashes with Turkish security forces on Saturday, the military said.
It was one of the highest casualty tolls in a single day of the conflict in recent years. Turkey's largely Kurdish southeast has been rocked by waves of violence following the collapse of a 2-1/2-year ceasefire between the state and the PKK last year.
The military said in a statement that more than 100 PKK militants had been "neutralized" in clashes, without specifying how many were killed and how many wounded. It said most had been taken back to northern Iraq, where the PKK has mountain camps.
Turkey's southeast has seen heavy fighting in recent days in Hakkari province, near the border with Iraq, and in Van province, near the border with Iran.
Five Turkish security force members were killed and six more were wounded in clashes in Hakkari, security sources told Reuters.
Eight more security force members were killed overnight in Van, the sources said.
More than 40,000 people, most of them Kurds, have died since autonomy-seeking PKK launched its insurgency against the Turkish state more than 30 years ago. The PKK is regarded as a terrorist organization by Turkey, the United States and the European Union.