Turkey believes Syria's new rulers, including the Syrian National Army (SNA) armed group which Ankara backs, will drive Kurdish YPG fighters from all territory they occupy in northeastern Syria, Defence Minister Yasar Guler said on Sunday.

Turkey regards the Syrian YPG as an extension of the Kurdistan Workers Party (PKK) militants who have fought an insurgency against the Turkish state for 40 years and are deemed terrorists by Ankara, Washington, and the European Union.

The YPG spearheads an alliance, the Syrian Democratic Forces (SDF), which is backed by the United States and controls territory in northeastern Syria. Since the fall of Syrian ruler Bashar al-Assad two weeks ago, Turkey and Syrian groups it backs have fought against the SDF, seizing the city of Manbij.

"We believe that the new leadership in Syria and the Syrian National Army, which is an important part of its army, along with the Syrian people, will free all territories occupied by terrorist organisations," Guler said during a visit to Turkish troops on the Syrian border with military commanders.

"We will also take every necessary measure with the same determination until all terrorist elements beyond our borders are cleared," he said in a video released by his ministry.

Ankara has demanded the Syrian Kurdish fighters disband, and has called on Washington to withdraw its support. The U.S. military acknowledged last week it has 2,000 troops on the ground in Syria, twice as many as it had said previously.

On Saturday, Turkish Foreign Minister Hakan Fidan said Turkey would do "whatever it takes" to ensure its security if Syria's new administration was unable to address its concerns.