Turkey is playing a risky game of chicken in its negotiations with NATO partners who want it to join combat operations against the Islamic State group — and it's blowing back with violence in Turkish cities.

As the Islamic militants rampage through Kurdish-held Syrian territory on Turkey's border, Turkey says it won't join the fight unless the U.S.-led coalition also goes after the government of Syrian President Bashar Assad.

The tactic has enraged Turkey's own Kurdish population, which accuses the Turkish government of standing idly by while their people are being slaughtered in the strategic border town of Kobani.

Turkey's strategy risks not only alienating its NATO partners, but also torpedoing one of Turkish President Recep Tayyip Erdogan's signature achievements: once-promising talks to end 30 years of bloody insurgency by the PKK, the Kurdish separatist guerrilla movement fiercely opposed by Ankara.

The Islamic State militants' advance on Kobani, even as Turkish forces have dug in within artillery range of the fighting, is already spilling violence into Turkey. Turkish Kurds, who believe their government is at best impeding efforts to defend Kobani are revolting across the country.

This week, the outrage turned volcano-like as Kurds clashed with police and supporters of an Islamist group in cities across Turkey, leaving at least 31 dead and scores injured. Among the casualities Thursday were three police officers killed in the eastern province of Bingol, and a police chief who was hospitalized with life-threatening injuries.

Turkish officials responded by imposing curfews in predominantly Kurdish regions. Kurdish leaders, including jailed PKK chief Abdullah Ocalan, have warned that the fall of Kobani will end the peace process.

Ocalan has led the peace talks with Turkey from a prison island off Istanbul, where he is serving a life term. Erdogan has offered concessions that would have been unthinkable in recent Turkish history.

Turkish officials say this week's clashes are part of a PKK strategy to win more leverage in the negotiations. In a mostly conciliatory statement released Thursday, Erdogan called for restraint and expressed sorrow for the dramatic violence. But he also spoke of "dark circles" provoking conflict for political gain.

"It is clear that this game is targeting the peace process and is intending to sabotage our ancient brotherhood, peace and tranquility," said Erdogan, who earlier this week reiterated that Turkey views the PKK as equally deplorable as the Islamic State group.

Kurds in turn accuse Erdogan of fueling the al-Qaida offshoot's rise as part of an all-out proxy war against Assad. Kobani is being defended by Kurdish fighters with ties to the PKK, which is considered a terrorist organization by Turkey, the U.S. and its Western allies.

The PKK has fought Turkey for autonomy for Kurds in a conflict that has claimed tens of thousands of lives since 1984. Kurds, who make up an estimated 20 percent of Turkey's some 75 million people, have faced decades of discrimination, including restrictions on the use of their language.

Sinan Ulgen, a former Turkish diplomat and visiting scholar at the Carnegie Endowment for International Peace, says some in the Turkish government see advantages to standing idly by as two of its enemies — the Islamic State militants and the Kurdish guerrillas — battle one another.

"The fact that the two are fighting each other is not necessarily a bad outcome for Turkey if you really want to think in pure realistic terms," he said in a conference call with reporters Thursday.

But he noted that others in the government realize that the strategy is harming Turkey's image and creating a dangerous dynamic with its Kurdish population. While the inaction frustrates allies, the renewed scenes of police violence could set back its European Union aspirations.

Against the backdrop of more violent protests Thursday at two Ankara universities, NATO chief Jens Stoltenberg and U.S. President Barack Obama's top envoy to the anti-Islamic State coalition, retired Gen. John Allen, arrived in the Turkish capital to discuss Turkey's role.

U.S. officials say that they have been surprised at how far Erdogan has been willing to go to press his demands.

"He seems ready to throw the peace process out the window over this," said one senior U.S. official, speaking on condition of anonymity because he was not authorized to comment. He added that the Obama administration is adamant about not expanding the mission and is highly unlikely to grant Turkey's demands.

This week's violence shows the high stakes facing Turkey, Ulgen said.

"A lot hinges on the negotiations with Washington, because if Turkey can start to adopt a more aggressive attitude towards (the Islamic State group), or start to engage in Kobani more, that will certainly pacify things domestically," he said.

"But if it doesn't do that, then of course Turkey may be faced with almost a perfect storm of security threats, with the resurgence of PKK violence and ISIS at the border," he said, referring to the Islamic State by an alternate acronym.

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