The Turkish army said two of its soldiers were killed and 31 wounded in an attack overnight by the Kurdistan Workers Party (PKK), as violence escalated following Ankara's air bombardment of Kurdish militants in northern Iraq.
The suicide attack was carried out with a tractor loaded with two tonnes of explosives on a gendarmerie outpost in the Dogubeyazit district of eastern Agri province, bordering Iran, the provincial governor's office and the army said.
Four of the soldiers injured in the attack in which PKK militants also used rifles were in serious condition, the army said.
Another soldier was killed in Turkey's southeastern province of Mardin when a unit on patrol was attacked by the PKK late on Saturday night, the army said. Seven soldiers were also wounded in the incident.
Armed attacks by PKK militants in southeastern Turkey have increased since mid-July, much more so since Turkey began a campaign of air strikes on PKK camps in northern Iraq on July 24.
In what prime minister Ahmet Davutoglu has called a "synchronized fight against terror," Ankara has granted access of its bases to the U.S.-led coalition battling Islamic State, however so far the majority of Turkey's air bombardment has been on PKK targets.
Turkish officials have said the strikes against the PKK are a response to increased violence. Sunday's attacks have brought the number of security forces killed in attacks blamed on the PKK to at least sixteen, since July 20.
In an opinion piece published in Washington Post on July 31, Davutoglu said the operations would continue. "All terrorist organizations that target Turkey must know that their acts will not go unpunished and that we will respond to their acts with full resolve," he wrote.
"This is not to say that the process of seeking a solution is over; on the contrary, I am determined to take it forward," he said.
Massoud Barzani, the president of Iraq's Kurdistan region on Saturday condemned Turkey's bombardment of a village there which he said had killed civilians, and called for a return to the peace process.
In his statement, he has also called on the PKK to distance the war from KRG territory. "The PKK forces must move the battlefields away from Kurdistan," he said.
Turkey's foreign ministry said it was working with the Kurdistan Regional Government (KRG) to investigate claims of civilian casualties in the village of Zargala on Friday.
Western allies, including NATO and the United States, have supported Turkey's actions but several have also urged it not to use excessive force or to let years of peace efforts with Kurdish militants collapse.
Turkish President Tayyip Erdogan initiated negotiations in 2012 to try to end the PKK insurgency, largely fought in the predominantly-Kurdish southeast and which has killed 40,000 people since 1984. The ceasefire, though fragile, had been holding since March 2013.
On Tuesday, Erdogan said the process had become impossible and urged parliament to strip politicians with links to the militants of immunity from prosecution.
The leader of Turkey's pro-Kurdish opposition has accused Erdogan of launching air strikes in Syria and Iraq to prevent Kurdish territorial and political gains, and of using the war against Islamic State as a cover. (Editing by William Hardy)