"Syria reiterates its categorical rejection of any American-Turkish agreement," a foreign ministry source told state news agency SANA.

Such a deal would "constitute a blatant attack on the sovereignty and unity of the country", the source added.

Turkey and the US began talks on Tuesday to establish a "security zone" in northern Syria aimed at creating a buffer between Kurdish fighters and the Turkish border.

The idea was first mooted by US President Donald Trump in January, in a call with his Turkish counterpart Recep Tayyip Erdogan, at a moment when Turkey was threatening to launch an offensive against Kurdish forces in Syria.

But Turkey said Wednesday it was not satisfied with the buffer zone solutions offered by the US.

"The latest US proposals are not satisfactory," said Foreign Minister Mevlut Cavusoglu.

"We should say things clearly: we have the impression that (the United States) is trying to buy time," he added.

The US has provided extensive support to the Syrian Kurdish YPG militia in Syria.

The YPG has led the fight against the Islamic State (IS) group in Syria, but Ankara sees it as a terrorist offshoot of Kurdish militants inside Turkey.

Turkey has launched two previous offensives into Syria against IS and the YPG, in 2016 and 2018.