PKK militants attacked a military police station in Turkey's south-east, killing two Turkish soldiers and injuring 31.
The suicide attack by the Kurds came after hundreds of air strikes on PKK positions in Turkey and Iraq by the Turkish military.
Turkey's state news agency, Anadolu, said a tractor carrying two tons of explosives was detonated by a PKK bomber.
The agency says about 260 Kurdish fighters have been killed in strikes in northern Iraq and Turkey since 24 July.
At least six people were killed and several wounded in further Turkish air strikes on Saturday east of Erbil, the capital of Iraqi Kurdistan.
The pro-PKK Firat news agency described an attack on the village of Zerkel as a "massacre".
Iraqi Kurdish President Massoud Barzani said: "We condemn the bombing, which led to the martyrdom of the citizens of the Kurdish region, and we call on Turkey to not repeat the bombing of civilians."