Assad tells Kurds US will not protect them
The US is set to pull out its soldiers from Syria after allied Kurdish-led forces capture the Islamic State group's last holdout in the war-torn country.
Any withdrawal risks leaving the Kurds exposed to a long threatened attack by neighbouring Turkey.
"We tell those groups who are betting on the Americans that the Americans will not protect you," Assad said in a televised speech.
"The Americans do not hold you in their heart... They will put you in their pocket so you can be a bargaining chip."
The looming prospect of a US withdrawal, announced in December, has sent Kurdish forces scrambling to rebuild ties with the Damascus regime, but talks so far have failed to reach a compromise.
"If you don't prepare yourselves to defend your country and resist, you will be nothing but a slave to the Ottomans," Assad warned, using a historic term for Turks.
"No one will protect you except your state. No one will defend you except the Syrian Arab army," he said.
The Kurdish-led Syrian Democratic Forces, which has fought IS with backing from the US-led coalition since 2015, on Sunday met to discuss "the future of relations with the Syrian government".
The SDF stressed the need for Damascus to recognise the "special status" of the Kurdish-Arab alliance, as well as the Kurdish semi-autonomous region.
In a statement, it also expressed a "willingness to solve problems with Turkey through dialogue," based on "mutual respect".
Nearly eight years into a war that has killed more than 360,000 people and displaced millions, Assad's forces control almost two thirds of the country.
Just two areas remain beyond its control: the rebel-held northwestern region of Idlib, and around a third of the country under control of Kurdish-led forces.
"Every inch of Syria will be liberated," Assad said in Sunday's speech.
Meanwhile the regime forces continued shelling on Idlib, killing 24 people this week alone.
The Syrian war began when Assad responded with military force to peaceful protests demanding democratic reforms during the Arab Spring wave of uprisings.
At least tens of thousands of civilians have been killed in the war, mostly by the regime and its powerful allies, and millions have been displaced both inside and outside of Syria.