Ten soldiers, eight civilians and the attacker died in a bombing in the south-east Turkish province of Hakkari on Sunday, Prime Minister Binali Yildirim was quoted by state-run Anadolu news agency as saying.
At least 16 soldiers were wounded when a pick-up truck laden with five tons of explosives went off in front of a checkpoint belonging to the Turkish gendarmerie in the district of Semdinli.
There were also assumed injuries among a group of civilians waiting at a nearby bus stop, but it was not clear how many, Anadolu reported. Earlier reports had spoken of 27 injured.
The Turkish army immediately pointed the finger directly at the outlawed Kurdistan Workers' Party (PKK), which later claimed the attack, saying it had killed 32 soldiers.
Turkish President Recep Tayyip Erdogan promised to go after the PKK until they were no longer in a position to carry out attacks.
"To do this, we are mobilizing everything that is necessary, from human manpower to technological possibilities," Anadolu cited the president as saying.
The Turkish army launched an offensive against the PKK last summer after a two-year ceasefire collapsed.
The PKK and its splinter group the Kurdistan Freedom Falcons (TAK) have since then carried out repeated attacks on Turkish security forces.
The government has ruled out reviving peace negotiations, with Deputy Prime Minister Numan Kurtulmus tweeting Sunday: "Turkey will never capitulate to terrorist organizations."
He said the perpetrators of Sunday's "abominable" attack would be called to account.