The Syrian Observatory for Human Rights said yesterday that pro-Turkish factions withdrew from Khan Sheikhoun and northern Hama (northwest), while Ankara warned Damascus against «playing with fire», the day after announcing that a military convoy of its air strike while heading to the Turkish observation point south of Khan Sheikhon, while Moscow accused armed factions of "provocations", and accused Ankara of supporting "terrorists", and warned of any attack on its soldiers in Idlib.

In detail, the observatory said on its website that after heavy clashes and intensive ground and air preparation, Syrian forces were able to enter the city of Khan Sheikhoun in the southern countryside of Idlib.

He explained that «it was able to enter the city from the north-west, and control of its northern and eastern neighborhoods after the withdrawal of terrorist factions from the south».

The Syrian Observatory documented more casualties due to shelling and ongoing fighting on the axes south of Idlib, where it rose to 40 people killed, including a military commander of the pro-Turkish corps.

He pointed out that 25 members of the Syrian forces were killed during the same battles.

He said that with more casualties, the death toll rises to 3,663 people who have been killed since the start of the fiercest escalation ever, within the area of ​​"de-escalation", on the 30th of last April, until Sunday, 18th of August.

Syrian forces have been trying for days to advance towards the strategic city of Khan Sheikhoun, the largest city of the southern countryside of Idlib, where a strategic highway linking Aleppo to Damascus.

Khan Sheikhoun is currently a semi-empty area that has fled to safer areas since the escalation began in the Idlib area months ago. It was home to about 100,000 people, most of whom were displaced during the past years.

The withdrawal of the factions came after the Syrian army forces seized more than half of the city and were able to block the Aleppo-Damascus International Highway in front of military reinforcements sent by Ankara on its way to the northern countryside of Hama, where Turkey's largest observation post is located in the town of Murk.

Part of the road runs through Idlib, linking the northern city of Aleppo to Damascus, and analysts say the regime wants to take control of it.

Observatory director Rami Abdulrahman said, "The Turkish observation point in Murk is now under siege, and its members have only left to withdraw through roads under the control of the regime on the ground or fire."

In response to the recent developments, Turkish Foreign Minister Mevlut Caoşoغلlu yesterday called on Damascus not to play with fire. "As we said earlier, we will do everything necessary to ensure the security of our military and our checkpoints," he told a news conference.

Ankara had announced, the day before yesterday, was subjected to her convoy after arriving in the southern countryside of Idlib, an air strike, which killed three civilians, but the observatory said they were opposition fighters.

The convoy, made up of about 50 armored vehicles, armored personnel carriers and logistic vehicles, as well as at least five tanks, was unable to complete its route to Murk after areas close to it were bombed, according to the Observatory, prompting it to stop since Monday afternoon on the international road. In the village of Maaratat north of Khan Sheikhoun.

Roads into the area on Tuesday are under aerial bombardment.

Idlib is covered by a Russian-Turkish agreement to reduce the escalation, and another agreement signed in Sochi in September, which provided for the establishment of a demilitarized zone that would separate the regime forces from the factions, with the jihadists withdrawing from it. The latest agreement averted an attack by Idlib, which Damascus has long waged, although it has not been completed.

Russian Foreign Minister Sergei Lavrov accused extremist militants yesterday of violating the agreement at the sight of Turkish observers, pointing to the deployment of Russian troops in the demilitarized zone, and continued communication with the Turkish army.

The day after Damascus condemned the Turkish reinforcements, President Bashar al-Assad, on Tuesday, his intention to restore all the territories beyond his control.

He said during a meeting with a Russian delegation that «the recent battles in Idlib revealed to those who had doubts, Ankara's clear and unlimited support for terrorists».

Al-Watan newspaper, which is close to Damascus, said in its issue yesterday that the Syrian army sent the day before yesterday «clear warning signals for any attempt to revive a new Turkish terrorists».

Under the agreement, Ankara will deploy several checkpoints in Idlib. Damascus accuses it of dragging its feet.

"Syria and its Russian ally have proved that Turkish observation points could complicate military progress on the ground," said Sam Heller, a researcher at the International Crisis Group. "They want to avoid inflicting casualties on Turkish soldiers, but these are not enough to deter them from moving forward."

It is unclear, according to Hiller, whether Damascus, with Russian support, will continue to advance on the ground, or just install its new positions.

After the signing of the Sochi Agreement, the relative calm was established before the regime forces stepped up their shelling at the end of April, and Russian planes later joined it. On the 8th of this month, it began to advance in the field in the southern countryside of Idlib.

Yesterday's shelling targeted several areas north of Khan Sheikhoun, including the village of Binin, where an AFP correspondent saw members of the Civil Defense pulling a man out of the rubble after miraculously surviving. After being rescued, he appeared in terror before being taken to the ambulance.

The escalation has killed more than 860 civilians, according to the Observatory, and the displacement of more than 400 thousand people, according to the United Nations.

Syria has been plagued by a bloody conflict since its outbreak in 2011 that has killed more than 370,000 people, caused massive destruction of infrastructure and displaced more than half of the population inside and outside the country.