The chaos in the areas targeted in the six-day-old Turkish assault has already led to the escape of around 800 foreign women and children linked to IS from a Kurdish-run camp
The Syrian regime sent troops towards the Turkish border on Monday to contain Ankara's deadly offensive against the Kurds, stepping in for US forces due to begin a controversial withdrawal.
Outgunned and without US protection, the autonomous Kurds in northeastern Syria had few other options to stop the rapid advance of Turkish troops and their Syrian proxies.
Turkey wants to create a roughly 30km buffer zone along its border to keep Kurdish forces at bay and also to send back some of the 3.6 million Syrian refugees it hosts.
The United States and its partners - who spent years fighting the Islamic State group in Syria before deserting them - have condemned the Turkish invasion but their threats of sanctions have failed to stop it.
The chaos in the areas targeted in the six-day-old Turkish assault has already led to the escape of around 800 foreign women and children linked to IS from a Kurdish-run camp, Kurdish authorities said.
The Kurds had repeatedly warned of that scenario when Western countries refused to repatriate their IS-linked nationals and when US President Donald Trump made it clear he wanted to end US military presence.
Wasting no time to fill the void, Moscow - already the top broker in Syria - clinched a deal between the Kurds and Damascus, whose ties had been icy since the minority threw its lot with Washington and unilaterally declared self-rule.
"In order to prevent and confront this aggression, an agreement has been reached with the Syrian government," the Kurdish administration said in a statement late Sunday.
The Syrian regime has sent troops towards the Turkish border to contain Ankara's deadly offensive against the Kurds, stepping in for US forces due to begin a controversial withdrawal https://t.co/AEn5FIr9UV— AFP news agency (@AFP) October 14, 2019
In an editorial published in Foreign Policy magazine, the head of the main Kurdish force wrote: "If we have to choose between compromises and the genocide of our people, we will surely choose life for our people."
By Monday morning, Syrian government forces were already moving to within several km of the border, AFP correspondents on the ground said.
Residents around the town of Tall Tamr welcomed regime forces with cheers and Syrian state television showed some of them waving national flags and portraits of President Bashar al-Assad.
According to a newspaper close to the Damascus regime, Syrian forces were also expected to deploy in the areas of Manbij and the border town of Kobane.
The main remaining flashpoint along the border was the town of Ras al-Ain, where Kurdish-led Syrian Democratic Forces have been putting up stiff resistance against Turkish air strikes and shelling for almost a week.
According to the Syrian Observatory for Human Rights, a monitoring group, the Turkish attack - which uses Syrian proxies on the ground - has already left 121 SDF fighters and 60 civilians dead.
An air strike on a convoy that included SDF fighters, civilians and journalists Sunday killed at least 10 people in the Ras al-Ain area.
Footage circulated by local media showed gruesome scenes taken moments after the hit, with bodies strewn amidst the convoy's vehicles.
AFP reporters said overwhelmed medics in a hospital in Qamishli struggled to treat the wounded, several of whom were in critical condition.
On the Turkish side, four soldiers and 18 civilians have been confirmed killed in six days, either in fighting or from Kurdish cross-border fire, according to Turkish sources.
The Observatory put the number of pro-Turkish Syrian forces killed in the offensive at 86.
An internal document circulated by the Kurdish administration on Monday, a copy of which was obtained by AFP, stressed the deal with Damascus was purely of a military nature and did not affect the work of the semi-autonomous institutions.
But the de-facto stateless the Kurdish administration had set up in northeastern has fast unravelled in recent days, with its forces losing control of a 120-kilometre-long segment of the border.
The area that is now under the control of Turkey and its proxies is ethnically Arab-dominated and some residents welcomed Turkish-backed forces.
Kurdish officials and residents alike in north-eastern Syria have expressed outrage at what they call a US betrayal that shortchanges the sacrifices made in the fight against IS.
Since 2014, the SDF have been the US-led anti-IS coalition's main partner on the ground in Syria, spearheading some key battles on the way to eliminating the jihadists' self-proclaimed "caliphate" earlier this year.
Trump already said last year he intended to pull US troops of Syria out but on Sunday the Pentagon announced he had ordered the withdrawal of 1,000 troops - almost the entire ground force - from the country's north.
"The United States has lost its defeat mechanism against the Islamic State," the Institute for the Study of War wrote in a brief.
"It took years for the US to realise that the SDF were the only capable partners. They will not partner with us again," it said.
France and other countries have voiced deep concern over the risk that the Turkish invasion would break out detained IS fighters, scattering them across the region and possibly beyond.
That fear was validated Sunday when Kurdish authorities said Turkish shelling near a camp holding hundreds of these foreign fighters' relatives - including often very radicalised women - led to a mass breakout.