A Syrian government statement demanding Turkish troops' withdrawal from the northwest city of Idlib is made to feed the domestic public opinion and should not be taken seriously, a senior MP with Turkey's ruling party has told Al Jazeera.

Damascus on Saturday urged "immediate and unconditional withdrawal" of Turkish troops that have been deployed to Idlib to back the Free Syrian Army (FSA) fighters, who are implementing a "de-escalation zone" deal agreed by Moscow, Ankara and Tehran in September.

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A Foreign Ministry statement carried on state media said the entry of Turkish forces in Idlib "was a violation of international law and was not tied with the understandings that were reached between the guarantor states in the Astana process," referring to Russia, Turkey and Iran.

The Syrian statement was made "to save the government's face" in the eyes of the public there, Kani Torun, a senior MP and the deputy chair of the Turkish parliament's foreign affairs committee, said.

"At the end of the day, foreign troops have entered the Syrian land and this has to be explained to the Syrian public in one way or another."

Russia, Turkey and Iran have agreed in the Kazakh capital of Astana in September to set up de-escalation zones for six months in various parts of the country.

Sergey Lavrov, Russia's foreign minister, said on Friday that the de-escalation zones "were conducted in the framework of the Astana talks with the participation of the three guarantor countries - Russia, Turkey and Iran - and assistance from US and Jordanian observers and UN representatives."

The Turkish army has started deploying troops and armoured vehicles to Idlib on October 8 and begun setting up observation posts in the city on Friday, according to statements by the country's General Staff.

A video distributed by the army showed what the General Staff said a convoy heading to pass the Syrian border on Thursday night, with military vehicles travelling in the darkness.

Hay'et Tahrir al-Sham, an alliance led by a former al-Qaeda affiliate, controls large parts of Idlib.

'Close cooperation with Russia'

Torun told Al Jazeera that the operation in Idlib was being implemented in close military coordination with Russia.

"Russian forces are responsible for protecting the borders of the city of Idlib, while Turkish forces are in charge of the internal security, making sure that the city does not harbour terrorist groups and no violence occurs there. This is the deal," he said.

"The role assigned the Russian forces' role in the outskirts of the city prevents any possible intervention in Idlib by Syrian government forces."

Torun said that there might be other such operations in the future as Turkey and Russia agree on the implementation of the zones.

Damascus had condemned Turkish incursions to Syria in the past, labelling them as "breach of Syrian sovereignty", such as the one made after Turkey and FSA's Operation Euphrates Shield launched in August 2016.

Turkey sent troops, tanks and warplanes into Syria in this major operation, which Ankara said, was aimed at pushing the Islamic State of Iraq and the Levant (ISIL, also known as ISIS) group away from the Syrian border and halting the advance of Kurdish fighters, whom Ankara views as an arm of the outlawed armed Kurdish fighters within Turkey.

Follow Umut Uras on Twitter: @Um_Uras