BEIRUT: The US-backed Syrian Democratic Forces would coordinate with Syrian government troops to fend off any Turkish invasion of the north, the SDF commander told Reuters on Sunday, saying Damascus should use its air defence systems against Turkish planes.

Ankara has vowed a new offensive on swathes of northern Syria controlled by the SDF, a Kurdish-led alliance that is spearheaded by the Kurdish People’s Protection Units (YPG).

The new threats have highlighted the complex web of ties in northern Syria: while Turkey considers the YPG a terrorist organisation, Syrian Kurdish forces are backed by Washington and have also coordinated with Syria’s government and its ally Russia.

SDF head Mazloum Abdi said on Sunday that his forces were “open” to working with Syrian troops to fight off Turkey but said there was no need to send additional forces.

“The essential thing that the Syrian army could do to defend Syrian territory would be use air defence systems against Turkish planes,” he said in an interview by telephone from an undisclosed location in northern Syria.

Syria sees Turkey as an occupying force in its north and the foreign ministry in Damascus said last month it would consider any new Turkish incursions as “war crimes and crimes against humanity”.

Turkey has backed rebel groups in clashes against Syrian President Bashar al-Assad’s forces and the SDF. It has used warplanes and increasingly drones to target territory held by the SDF, where Syrian Kurdish authorities have set up a governance system separate from Damascus.