ANKARA/DIYARBAKIR (Reuters) - The Turkish military ratcheted up pressure on Kurdish militants with a fresh round of air strikes in the southeast of the country on Tuesday as the insurgents claimed responsibility for the bombing of a police station in Istanbul.

A Turkish Air Force F-16 fighter jet lands at Incirlik air base in Adana, Turkey, August 11, 2015. REUTERS/Murad Sezer

Warplanes pounded 17 targets in the province of Hakkari on Monday and Tuesday, the military said, part of a renewed crackdown on the outlawed Kurdistan Workers Party (PKK) which has waged a three-decade insurgency for Kurdish autonomy.

NATO member Turkey started what it called a “synchronized war on terror” last month, attacking PKK fighters in northern Iraq and, less frequently, Islamic State militants in northern Syria.

By largely focusing on the PKK - both in neighboring Iraq and at home - Ankara has raised suspicions among Kurds that its real agenda is to check Kurdish territorial ambitions rather than to crush the hardline Islamists.

Critics accuse President Tayyip Erdogan of attempting to use the violence to win back nationalist support after a stinging election setback for the ruling AK Party in June.

“Our fight will continue until not one terrorist is left within our borders and until concrete is poured over (their weapons),” Erdogan said at a military ceremony on Tuesday.

The PKK claimed responsibility for Monday’s bombing of the police station in which four people died, three of them attackers. The bombing was one of a wave of attacks on Turkish security forces that have killed at least nine people.

“DAMAGE THE ENEMY”

In a statement published online, the PKK named the three of its militants who died in the attack and the subsequent firefight. It also called for a focus on attacks that “damage the enemy” rather than just sacrificing the fighter.

The air strikes in Hakkari followed operations on Sunday in the eastern Agri province, which killed seven PKK militants, according to the local governor’s office.

In ground fighting, security sources said the PKK attacked a military station in Sirnak, a province adjacent to Hakkari, and killed one soldier in a 20-minute battle.

The military later confirmed its forces had come under attack in Sirnak and had launched air strikes to take out two PKK heavy machine gun positions.

One PKK militant was also killed in a clash in Bingol province, the local governor’s office said.

The United States and the European Union, like Turkey, classify the PKK as a terrorist organization.