Syria’s army has started to reach the north of the country, hours after the government agreed to help Kurdish forces facing Turkey.
State media said government forces, which are backed by Russia, had entered the strategic town of Tal Tamer, 30km (19 miles) south of the Turkish border.
The deal came after the US, the Kurds’ main ally, said it would withdraw its remaining troops from northern Syria.
Turkey’s offensive aims to push Kurdish forces from the border region.
Areas under the control of the Kurdish-led Syrian Democratic Forces (SDF) came under heavy bombardment over the weekend, with Turkey making gains in the key border towns of Ras al-Ain and Tal Abyad.
Dozens of civilians and fighters have been killed on both sides.
On Sunday, US Defence Secretary Mark Esper announced the Pentagon was moving up to 1,000 troops away from the north, citing fears that US forces would end up stuck between “two opposing advancing armies”.
The Turkish offensive and US withdrawal have been internationally criticised, as the SDF were the main allies of the West in defeating the Islamic State (IS) group in Syria. There are fears about a possible resurgence of the group and the escape of prisoners amid the instability.
According to the Kurdish-led administration in northern Syria, Sunday’s agreement will allow the Syrian army to deploy along border areas controlled by Kurdish forces to “repel [Turkish] aggression”.
It is the first time government troops will enter those areas since 2012, when forces loyal to President Bashar al-Assad withdrew to fight rebels elsewhere, letting Kurdish militias take control.
The deal represents a significant shift in alliances for the Kurds, who said they had been “stabbed in the back” by President Donald Trump after he pulled dozens of US troops from pockets in the north-east last week.
The move effectively paved the way for the operation by Turkey, which views elements of the Kurdish groups in Syria as an extension of the banned Kurdistan Workers’ Party, which has fought for Kurdish autonomy in Turkey for three decades.
Apart from being important partners in fighting IS in Syria, the Kurds were fundamental for Washington in limiting the influence of Russia and Iran, key allies of President Assad and US rivals, and keeping some leverage on the ground.
For now, Syrian forces will not be deployed between Tal Abyad and Ras al-Ain, where Turkey has focused its efforts. Apart from Tal Tamer, government troops also entered Ain Issa, according to state media.
