Istanbul: Two more Turkish police were killed Friday in an attack blamed on Kurdish militants as tensions in the country boiled over amid the military`s cross-border bombing campaign against extremists in Syria and Iraq.
With Prime Minister Ahmet Davutoglu vowing to pursue the bombing campaign to the end, criminal investigations were also opened against the co-leaders of Turkey`s largest pro-Kurdish party.
Ankara has launched a two-pronged anti-terror offensive against Islamic State (IS) jihadists in Syria and Kurdistan Workers Party (PKK) militants at their bases in northern Iraq after a wave of deadly attacks in the country.
But so far air strikes had targeted mainly the PKK, which is itself bitterly opposed to IS, raising tensions in Turkey with its large Kurdish minority.
Deadly attacks on the security forces blamed on the PKK have become a daily event, raising fears of a return to the dark days at the peak of its separatist insurgency in the 1990s.
In the latest violence, two Turkish police were killed in a gun attack on a police headquarters in the southern region of Adana.
Suspected PKK gunmen fired on police headquarters in the city of Pozanti, sparking clashes which left two police as well as two militants dead, the Anatolia news agency said.
According to an AFP tally, at least 13 members of the security forces have been killed in attacks blamed on the PKK in 10 days of violence.
Some 30 Turkish F-16 planes on Friday launched a new wave of strikes against PKK targets in northern Iraq, NTV television said.
"The operations will continue until weapons are laid down, armed groups leave Turkey and Daesh stops being a threat in Syria," Davutoglu said, using an Arabic acronym for IS.
"If needed, we are ready to sacrifice our sons and ourselves for this homeland," he told a conference in Ankara.The first shots were also fired in what may prove a long-running legal process against pro-Kurdish political forces, with prosecutors announcing probes against the both co-leaders of the pro-Kurdish Peoples` Democratic Party (HDP).
Its charismatic male co-leader Selahattin Demirtas is accused of inciting people to take up arms during October 2014 protests that left dozens dead, Anatolia said.
If the case comes to court, he could face up to 24 years in jail, it added.
Meanwhile, prosecutors Friday announced a probe against its female co-leader Figen Yuksekdag -- the party splits its top post between a man and a woman -- for "making propaganda for a terror group".
The investigation relates to comments Yuksekdag made on July 19 supporting Syrian Kurdish groups which Turkey links to the banned PKK.
As a riposte, Demirtas filed a complaint with Ankara prosecutors requesting a criminal investigation against Davutoglu and President Recep Tayyip Erdogan.
He said they should be charged with seeking to influence the judiciary with comments that encouraged criminal proceedings against the HDP and its leaders.
The PKK`s more-than-three-decade-long insurgency for greater rights and powers for Turkey`s Kurdish minority has left tens of thousands dead. The current violence has ripped apart a ceasefire declared in 2013.
German Foreign Minister Frank-Walter Steinmeier urged Turkey not to abandon the Kurdish peace process despite the tension. Demirtas accuses Erdogan of orchestrating the current security crisis in the hope of calling early elections to secure an outright majority for the ruling party after its lacklustre performance in June 7 polls.
With Turkey still without a permanent government as coalition talks drag on, Erdogan said early elections should be called "immediately" if the negotiations fail.
"If we expect them (coalitions) to bring benefits to our country, it is in vain," Erdogan told reporters on his plane while travelling on an official visit from China to Indonesia, the Hurriyet newspaper and other media reported.
Speaking in Indonesia, he also fiercely denied as "black propaganda" suggestions Turkey had assisted IS in the past.
Turkey is now set to open its Incirlik base outside Adana to US warplanes to bomb IS in a long-awaited move.
The Radikal daily online quoted an official as saying Turkey was waiting for US Air Force units to arrive at Incirlik before beginning broader operations against IS.
The CNN-Turk channel reported that 30 US F-16s and F-15s from the 480th squadron in Germany are due to arrive in Incirlik in two weeks.