Syrian President Bashar al-Assad on Tuesday said the government would support Kurdish fighters in the northeast of the war-torn country against Turkish soldiers and their Syrian proxies.
"We are prepared to support any group carrying out popular resistance against the Turkish aggression," he said in a video shared by the presidency.
"This is not a political decision... We are not taking any political decisions now," he told government troops on the frontline in the province of Idlib.
"It is a constitutional duty and a national duty," he said.
Turkey and its Syrian proxies on October 9 launched a cross-border attack against Kurdish fighters in northeastern Syria after an announced US military pullout.
Turkey wants to set up a buffer zone in Syrian soil along the length of its southern frontier to keep Kurdish forces it views as "terrorists" at bay.
Under a US-brokered truce deal announced last week, the Kurds have until late Tuesday to pull out their fighters from a 120-kilometre (70-mile) long strip along the frontier that it has largely overrun during the operation.
The Kurdish-led Syrian Democratic Forces have been a key ally of the United States in the battle against Islamic State group in Syria, at the cost of 11,000 fighters.
The US pullout has largely been seen as a betrayal of Syria's Kurds, who have spent most of the country's civil war working towards autonomy.
Damascus has previously accused Kurds of treason over their alliance with Washington.
The Turkish attack forced the Kurds to seek aid from the government and make a deal to deploy Assad's forces in some northeastern areas for the first time in years.
The government has since deployed in the border town of Kobane as well as the town of Manbij further south, without clashing with Turkish forces.
Assad has repeatedly said he would eventually restore government control over all parts of Syria, driving out rebels and jihadists.