A tractor laden with explosives was driven at a military police station, a statement said.
The attack happened early on Sunday near the town of Dogubayezit in Agri province, near the 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.
A Turkish state news agency, Anadolu, said the tractor was carrying two tons of explosives that were detonated by a suicide bomber.
Turkey's army said in a statement that "long-range guns" were also found. Four of the injured were in a serious condition.
The statement said the Karabulak Gendarmerie Station was hit at around 03:00 local time on Sunday (midnight GMT).
Images in the Turkish press showed a badly-damaged building with the roof destroyed.
One report said the blast was so strong that houses in a village several hundred metres away were hit by debris and some residents were slightly injured.
The Dogan news agency added that militants also set up ambushes on roads to prevent medical teams getting to the scene.
There has been no comment from the PKK so far.
AFP news agency said it would be the first time the group was accused of deploying a suicide bomber during recent clashes.
Turkey says the group was behind a number of attacks in the last two weeks:
Turkey's official news agency says about 260 Kurdish fighters have been killed in strikes in northern Iraq and Turkey since 24 July. It has also targeted positions held by the Islamic State group.
At least six people were killed and several wounded in further Turkish air strikes on Saturday east of Erbil, said local officials.
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."
The Turkish military on Sunday said it had investigated the incident and dismissed claims that there could have been civilian casualties in Zerkel, Reuters reported.
Turkey considers both the PKK and IS terrorist organisations.
The PKK has been fighting Turkey for an autonomous homeland for the Kurds.
More than 40,000 people have been killed and hundreds of thousands displaced since the PKK began an armed uprising in 1984.
In 2012, the government and PKK began peace talks and the following year a ceasefire was agreed.
However, the ceasefire ended in effect when Turkey launched raids against Kurdish separatist camps in northern Iraq last month.
The raids came after the PKK reportedly killed two Turkish police officers in retaliation for an attack claimed by Islamic State and what the PKK sees as Turkey's collaboration with IS.
Two Turkish soldiers have been killed and 31 wounded in a suicide attack by Kurdish PKK militants, the Turkish military says.