The Syrian government on Saturday demanded “immediate and unconditional” withdrawal of Turkish troops that have crossed to the northwestern province of Idlib, state news agency SANA reported citing the country’s foreign ministry.

The new Turkish military operation, which began on Thursday night, aims to enforce a de-escalation zone in Idlib, currently under the control of Hay'et Tahrir al-Sham (HTS), an alliance of five militant groups including members of Al-Qaeda affiliated group, Al-Nusra Front.

Four ceasefire zones have been agreed on by Ankara, which backs the Syrian opposition, Moscow and Tehran, staunch supporters of Syrian President Bashar al-Assad, during talks in the Kazakh capital earlier this year.

Three zones have already been set up, namely in Eastern Ghouta outside Damascus, central Homs, and parts of southern Syria, but the one in Idlib is yet to come into existence.

The Syrian government however denied that the deployment of Turkish armed forces had been agreed on in the latest round of Ankara talks, calling the Turkish move a “blatant aggression against the sovereignty and territorial integrity of the country.”

HTS has not been involved in the peace negotiations and had rejected any de-escalation zone in Idlib, where its hand has been strengthened after driving out other rebel factions in previous months.

Over 100 soldiers and 30 armored vehicles were deployed to Idlib on Thursday night where troops began establishing “observation posts.”

Turkish newspaper Hurriyet Daily expected more troops to enter the Syrian province in the following days. On Saturday, the London-based Syrian Observatory for Human Rights said a new Turkish convoy made its way to Idlib.

The current Turkish operation was preceded by a massive build-up.

Last week, Turkish President Recep Tayyip Erdogan announced that the Free Syrian Army, the Ankara-backed armed Syrian opposition that seeks to topple Assad, has initiated an operation against HST fighters, noting that the offensive was coordinated with Russia. The move came on the heels of a meeting between Erdogan and his Russian counterpart Vladimir Putin in Ankara, where the two agreed over the need to demarcate the Idlib de-escalation zone.

The Syrian foreign ministry was quoted as saying that Turkish troops entering Idlib were accompanied by members of Al-Nusra Front, arguing that it is an evidence of the "close relation between Turkey and the terrorist groups."

Ankara has the "high hand in supporting the terrorists in Syria and cannot be credible by claiming to be fighting terrorism," the ministry noted.

There is also wide speculation that Turkey’s military move goes beyond fighting terrorist groups and securing its borders with Syria. 

Idlib neighbors the Afrin area in Aleppo province, an enclave controlled by the US-backed People's Protection Units (YPG), a Kurdish militant group that forms the backbone of the Syrian Democratic Force and which Turkey has long been trying to contain.

(With inputs from Xinhua News Agency)