The YPG,or People's Protection Units,have proved to be one of the most effective forces against IS,providing vital ground troop support for the US-led coalition air strikes against IS militants in Syria. They won the Syrian border town of Kobane from IS and went on to secure another strategic Syrian border town,Tel Abyad,last month,cutting off a key IS supply route for weapons and fighters and expanding the territory under Kurdish control inside Syria.
"It is not clear yet if or how that ISIS-free zone is going to materialise,how it would be protected or what it would be used for,"said Cale Salih,a visiting fellow at the European Council on Foreign Relations.
"There is a lot of fear amongst Kurds that Turkey will use that kind of zone to target the PYD or at least to restrict it in terms of the PYD's quest for more territory that would link Afrin and Kobane,which is one of their main strategic goals in Syria."
The PYD,or Democratic Union Party,along with the YPG is an affiliate of the PKK or Kurdistan Workers Party,which waged a decades-long armed struggle against Turkey. But,Ms Salih points out,the PKK has a new mission in Syria which has very little to do with resistance against Turkey.
"It is really about establishing an economy in northern Syria,it is about linking the two cantons,fighting jihadists,and that is a real opportunity for the peace process and a chance for the PKK to move away from this identity that it has had for so long which is about resistance in Turkey."
After holding out for almost a year,Turkey entered into an agreement with the US on Friday thatwill allow US war planes to launch air strikes from Turkey's Incirlik Air Base. Soon after Turkey began bombing IS targets in Syria and on Saturday it also began attacking on Kurdish targets in northern Iraq.
"A lot of people are quite alarmed that Turkey has gone after ISIS and the PKK at the same time because it invites retaliation from both inside Turkey,"Ms Salih warned.
"That could seriously destabilise south-eastern Turkey … and present a genuine national security threat for Turkey in terms of ISIS."
NATO Secretary-General Jens Stoltenberg,who was due to chair Tuesday's extraordinary closed-door session,expressed solidarity with Turkey after"recent heinous terrorist attacks",but cautioned against abandoning its peace process with the Kurds.
For years"there has been progress to try to find a peaceful political solution",he told Norwegian state broadcaster NRK."It is important not to renounce that ... because force will never solve the conflict in the long term."
Syriac-Assyrian Christians in Syria also urged NATO to refrain from allowing Turkey to launch attacks against Kurdish positions in Syria.