Turkey has shot down a Russian warplane that crossed into its airspace amid tension over Russia's targeting of ethnic Turkmen forces in Syria which Turkey considers its "brothers and sisters."

Since Russia's bombing campaign in Syria began about two months ago Russian jets have repeatedly crossed into Turkish airspace. Until now Turkey has been relatively sanguine about those incursions (though it did send a couple of military helicopters into Armenian airspace which observers interpreted as a message to Russia). 

But by Tuesday, Ankara's patience had apparently worn out. After what Turkey claimed was a 17-second violation of its airspace, and ten warnings, Turkish F-16 jets shot down the Russian Su-24. It was apparently the first exchange of fire between a NATO member and Russia since the end of the Cold War. 

Turkey's decisionmaking was likely heavily influenced by the fact that Russia had of late been targeting units of ethnic Turkmens, culturally and linguistically close to Turks, in northern Syria. “That definitely played a role in how they responded to this incursion as compared to other ones," said Aaron Stein, a fellow at the Washingon-based Atlantic Council, in a conference call with reporters.. "This isn't just another Russian bombing campaign” but one that attacks what Turkey considers to be its sphere of influence, Stein added.

On Friday, Turkey summoned Russia's ambassador to protest the attacks. On Monday, Turkey called for a U.N. Security Council meeting on the attacks on Turkmens.

"The ongoing intense aerial bombardment which reportedly included use of cluster bombs by the Russian air forces and the land offensive by the Syrian regime forces, supported by Hizbullah militias have caused heavy civilian casualties," Turkey wrote in a letter to the UNSC. 

And the issue has become a cause celebre in the Turkish press. "The Turkish people are deeply concerned that their Turkmen brothers and sisters are being butchered by Assad," wrote Ilnur Cevik, a columnist for the pro-government Daily Sabah, in a commentary written just before the attack.

"And this is being done with Russian and Iranian help only a few kilometers off the Turkish border and there are growing demands by the Turkish public opinion for Turkey to 'do something' as the international community led by the United States are just watching the carnage."

Turkish President Recep Tayyip Erdogan, in a statement after the shootdown, referenced the Turkmens. “We strongly condemn attacks focusing on the places where Bayırbucak Turkmens live. We have relatives and cognates living there,” he said. (Bayırbucak is the region of northern Syria where these Turkmens live.)

The invocation of Turkic solidarity may be opportunistic from Ankara's perspective -- note that Turkey didn't respond more than rhetorically to Russia's annexation of Crimea, which was strongly opposed by the Turkic Crimean Tatars there. Nevertheless, that the attack on Turkic brothers and sisters was Turkey's breaking point is surely under consideration in the many other Turkic regions between Russia and Turkey, like the Caucasus and Central Asia, and is placing many of those countries in awkward positions.