Former United States Ambassador to Turkey James F. Jeffrey was appointed as Washington's Special Representative for Syria Engagement in a swearing-in-ceremony on Friday at the Department of State.

Jeffrey, who was the U.S. ambassador in Ankara from 2008 to 2010 and most currently a fellow with the Washington Institute, is known for his stark views on Iran and Russia. With regards to Syria, he has often criticized the U.S. arms support to the PKK's Syrian affiliate, the People's Protection Units (YPG), particularly regarding Ankara's concerns over the YPG.

Jeffrey's ceremony was seen in Secretary of State Mike Pompeo's schedule for Friday.

In a comment to Daily Sabah in September 2017, Jeffrey had said Ankara was "right about the PYD-PKK-SDF [Syrian Democratic Forces] relationship and thus Turkey has every right to be concerned and press Washington constantly for reassurances and details re U.S.-YPD ties."

"Turkey again is right to be concerned about possible risks to Turkey of U.S. strengthening the PYD and thus the PKK but the U.S. is aware and will try to counter that [taking back weapons issued, limiting types of weapons]. The U.S. this time will do better on Turkey's concerns than were seen with [former President Barack] Obama," former Ambassador Jeffrey had said in the same interview. Yet, time has shown that the U.S. President Donald Trump has followed suit on Obama's Syria policy with regards to support to the YPG in Syria.

Jeffrey has said in his comments regarding Syria policy that the YPG in Syria should not be allowed to form an autonomous state of its own, and had argued that both Turkey and the U.S. should also consider how they will tackle the increasing influence of Iran and Russia for their mutual long-term interests in the region.

Turkey and the U.S. have major differences in Syria. While Ankara sees the YPG as the offshoot of the PKK, a group recognized as a terrorist organization by the U.S., the EU, and Turkey, Washington has partnered with the YPG under the pretext of the fight against Daesh, with truckloads of weaponry and military equipment supplied to the group.

In June this year, in another comment to Daily Sabah, Jeffrey had said: "For the U.S. military, the YPG is an ally against Daesh. For Turkey it is part of the PKK and thus an existential threat. The U.S. has an obligation to ensure nothing it does while cooperating with the YPG endangers Turkish interests."

The former envoy had also made positive remarks in the same comment to Daily Sabah about the Manbij deal, between Turkey and the U.S., over bringing stability to the northern Syrian province and withdrawal of the YPG terrorists from the province. Jeffrey stressed that he is confident that the deal will be implemented successfully "but both sides should stay in close contact to resolve any problems quickly and quietly."

In addition to Ankara's concerns over the YPG, how Jeffrey will shape the Syria policy with regards to Iran and Russia are also matters that may indirectly affect Washington-Ankara relations and the nearly 8-year-old crisis in the country.