U.S. military support for Syrian Democratic Forces (SDF), which are led by the Kurdish YPG militia, have left Turkey furious. Officials have even warned that Turkish troops are ready to cross into neighboring Syria... Erdogan has also warned of an imminent incursion into Kurdish-controlled Afrin in northwest Syria... With around one-fifth of Turkey’s population identifying as Kurdish, Turkey views the PKK and moves toward Kurdish independence regionally as an existential threat... "The U.S. is directly providing arms to a group ... whose ultimate ambition is not defeating ISIS," said Ziya Meral, a Turkey analyst at the Centre for Historical Analysis...