The Syrian government’s announced offensive against rebel-held Idlib province could further complicate an already tense relationship between Turkey and the United States, both members of the Northern Atlantic Treaty Organization, if Kurdish armed militias were to join the battle alongside the forces loyal to President Bashar al-Assad of Syria.

It has been reported by Turkish and European media that Kurdish People’s Protection Forces (YPG) fighters, whom the Turks consider affiliated to the rebel PKK (Kurdistan Workers’ Party) movement in Turkey, may help the Assad regime and its Russian and Iranian allies retake Idlib.

In a letter to The New York Times on Thursday, Turkish Foreign Minister Mevlut Cavusoglu also suggested that Kurdish militants might aid the Syrian government in recapturing the last rebel stronghold, which is currently dominated by a jihadist umbrella group with connections to al-Qaeda and a rival front associated with Ankara that comprises a number of armed factions.

“It looks to me that this is happening, and I would describe the YPG as being co-belligerent with the Assad regime.” Soner Cagaptay, director of the Turkish Research Program at the Washington Institute for Near East Policy, told me. For its part, the US Embassy in Turkey could not confirm reports in the Turkish media when contacted.

Unsatisfactory cooperation

Turkish President Recep Tayyip Erdogan has so far failed to persuade Moscow and Tehran to reach a ceasefire in Idlib. Turkey is concerned that a showdown in the northwestern Syrian region will lead to a new influx of refugees across its borders. What’s more, should Assad take back Idlib, he could use it to launch operations against areas in Syria’s north that are controlled by the Turkish military and its local proxies.

This is a nightmare scenario for Ankara. And it may even be worse with the participation of Syrian Kurds in the looming battle. YPG militias control about one-third of Syria and have direct access to Kurdish-inhabited territory in Turkey. Under the banner of the Syrian Democratic Forces (SDF), which also includes Arab fighters, and with the active support of the US, the YPG has contributed to the defeat of the Islamic State (ISIS) terror group as a territorial entity in Syria.

Leaders in Ankara suspect that Washington is not willing to intervene to prevent its Kurdish partners from joining hands with Assad and its acolytes in Idlib. Ahmet Berat Conkar, a member of the Turkish Parliament for the ruling Justice and Development Party (AKP), said that “Washington’s cooperation with Turkey regarding PKK terrorists and their YPG affiliates in Syria is not satisfactory.”

Conkar, who heads Turkey’s delegation to the NATO Parliamentary Assembly, emphasized that Turkey and its allies in the Syrian opposition “will target the PKK/YPG terror group either in Idlib or elsewhere.” He insisted that YPG militants were a national-security threat for his country, and should be considered in the same way by Turkey’s NATO allies.

Developments in Afrin and Manbij

The US turned a blind eye to Turkey’s military operations to drive Kurdish fighters from Syria’s northwestern canton of Afrin last winter. The tactical entente with Moscow that allowed Ankara to wrest most of this area from the YPG appears to be faltering, and some wonder if Syrian Kurds will try to use the conflict in Idlib to launch an assault on Afrin – an operation that could also trigger a spat with the US.

Joshua Landis, director of the Middle East Center at the University of Oklahoma, does not believe that “retaking Afrin is part of the present Syrian offensive against Idlib.” In his opinion, this battle will not jeopardize Washington’s partnership with the YPG, as the common interests of the two parties in northern Syria are “strong and ongoing.”

The fact that the US and Turkey still disagree on the future status of Manbij supports the idea that Washington will do its best to protect its Kurdish assets in Syria. All the more so if the YPG do not reach a settlement with the Assad regime on the reorganization of Syria – talks on the issue are under way between the two sides, according to reports – and his forces launch an assault on Kurdish-dominated areas in eastern Syria in retaliation.

Turkey wants Kurdish forces to withdraw from Manbij, which lies west of the Euphrates River and near a Turkish-controlled zone. Washington and Ankara agreed on joint military patrols around the Syrian town in June, but their implementation has been delayed, while there is no clear agreement between them on the demobilization of YPG fighters from the area.

Manbij is controlled by SDF militants, and situated at a strategic point that gives them relatively rapid access to Idlib and Afrin by passing through zones administered by the Assad government. It comes as no surprise that US ambiguity on the control of this key crossroads town has angered Turkey.