The Turkish defense minister announced that the army has begun bombarding Kurdish-held regions along the Syrian border as Ankara looks to destroy a U.S.-backed border force made up largely of Kurdish militias.

The border force was created by the U.S. and the Kurds to prevent ISIS from concentrating its forces and threatening Iraq and Syria.  But the Kurds also see the force as protecting the autonomous area they've carved out independent of the Syrian government.

This has angered President Erdoğan, who has vowed to destroy the "terrorists" on the border.

Reuters:

Direct military action against territory held by Kurdish militia would open a new front in Syria's civil war and would see Ankara confronting Kurds allied to the United States at a time when Turkey's relations with Washington are reaching breaking point.

"The operation has actually de facto started with cross-border shelling," Turkish [defense m]inister Nurettin Canikli said, adding that no troops had crossed into Afrin.

A U.S. State Department official said such moves would undermine regional stability and would not help protect Turkey's border security.

"We do not believe that a military operation serves the cause of regional stability, Syrian stability[,] or indeed Turkish concerns about the security of their border," the official told reporters, stressing he had limited information about Turkey's reported military moves.

"The kind of threats or activities [that] these initial reports may be referring to, we don't think advance any of these issues. They are destabili[z]ing."

The United States has instead called on Turkey to focus on the fight against Islamic State militants and not take military action in Afrin.

As Turkey slips farther away from the west and Erdoğan continues to aggregate power and transform the country into an Islamic state, the U.S. and NATO have been powerless to stop him.  But Erdoğan has a stubborn Kurdish problem made worse by a terrorist militia living within Turkey, the PPK.  The U.S. recognizes the PPK as a terrorist outfit, but the militias in Afrin are associated with the YPG – an entirely different organization that has fought side by side with the U.S. in battling both ISIS and insurgents in Iraq.

But Erdoğan has chosen to lump all Kurdish militias together and refer to them as "terrorists."  He knows better but finds it politically convenient to demonize all the Kurds.  Besides, the prospect of an independent enclave of Kurds on his border makes Erdoğan uncomfortable. 

The U.S. can do nothing to help the YPG, as the bombardment probably presages a ground action against that group.  We have supplied the Kurds with mostly small arms, while to repel an armed invasion, they would need artillery and anti-tank weapons.  This, they are not going to get from Washington, or anywhere else.  But the Kurds are used to being on their own and, given their prowess on the battlefield, will give the Turkish army all it can handle.