A tractor laden with explosives was driven at a military police station, reports by Turkish media say.
The attack happened near the town of Dogubayazit in Agri province, close to Turkey?s border with Iran.
Since 24 July, Turkey has carried out hundreds of air raids on PKK bases on both sides of the Iraq-Turkey border.
The Turkish state news agency, Anadolu, said that the attack happened at around 03:00 local time (00:00 GMT).
It said that the tractor was carrying two tons of explosives that were detonated by a suicide bomber.
Images in the Turkish press showed a badly-damaged building with the roof destroyed.
The regional governor did not say how the PKK had been identified as the group behind the blast. The PKK has not commented.
Turkey says the group was behind a number of attacks in the last two weeks. On Friday, five people died when a police station and a railway line were targeted.
Turkey?s official news agency says about 260 Kurdish fighters have been killed in strikes in northern Iraq and Turkey since 24 July.
Further Turkish air raids were reported early on Saturday, this time in the Rawanduz area east of Erbil, capital of Iraq?s Kurdish region.
At least six people were killed and several more wounded in the town of Zarkel, local officials said. They reportedly included at least two women.