"Turkish Armed Forces elements that are to serve in the Idlib de-escalation zone have started their activities by establishing observation posts from October 12, 2017, as part of the Astana agreement..."
Over 100 soldiers, including special forces and 30 armoured vehicles entered Idlib, Turkey's Hurriyet daily reported on Friday, as it speculated more troops could be sent to the province over the next few days.
"The allied Turkish armed forces have entered Syrian territory and begun setting up observation posts", Mustafa Sejari, an official in the so-called Free Syrian Army (FSA) rebel group, was quoted as saying by Reuters. Turkey's declared aim is to eliminate groups affiliated with Al Qaeda from the border area and counter the expansion of the Kurdish rebels.
As part of the latest victories by the Syrian Army against Daesh (ISIL) terrorist group, the government troops on Thursday advanced in al-Mayadeen city in Deir ez-Zor, east of Syria. Reconnaissance units have been operating in the area since last Sunday.
The fourth de-escalation zone includes Idlib but also parts of the neighbouring Latakia, Hama and Aleppo regions.
The operation in the northwestern region was launched under a May deal between Turkey, which backs groups opposed to Syrian leader Bashar al-Assad's regime, and Russian Federation and Iran, who support Assad.
In the area taken by the Euphrates Shield campaign, Turkey has made changes to local governance that indicate it may be laying a foundation for long term ties with that part of Syria.
Idlib is one of the last remaining strongholds of the rebels, which has recaptured vast swathes of territory from opposition fighters since Moscow intervened on its behalf in September 2015.
However, the deployment is also meant to rein in the Kurdish YPG militia, which holds the adjacent Afrin region, a senior rebel official involved in the operation said.
Last week Turkish President Recep Tayyip Erdogan has announced new operation in Syria.
"Turkey is not after anything in Idlib but (an) Afrin siege could ignite fire of another war in the region", the YPG said on Twitter.