Two Turkish security troops have been killed and 31 wounded in a suicide attack by Kurdish PKK militants, the regional governor's office says.
A tractor laden with explosives was driven at a military police station, reports by Turkish media say.
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.
The Turkish state news agency, Anadolu, said that 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, it said.
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.
AFP said it would be the first time the PKK 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:
- On Sunday, a Turkish soldier was killed and four others hurt when a mine exploded under their convoy in the south-east of the country
- On Friday, five people died when a police station and a railway line were targeted
- On Thursday, three troops died in the southern Sirnak province after gunmen opened fire on their convoy
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, said local officials in eastern Turkey.
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.