Syrian President Bashar al-Assad said Damascus would have to "wait and see" if US President-elect Donald Trump would change Washington's policy on Syria but that he was ready to cooperate with him in fighting militants.
In his first comments on Mr Trump's election victory, Mr Assad said the President-elect had made promising comments on the need to battle Islamists in Syria's war but "can he deliver?"
"What about the countervailing forces within the (US) administration?" Mr Assad told a Portuguese television channel in remarks released by Syrian state television, pointing to what he said were rival "lobbies and powers" within the administration that traditionally influence any incumbent US president.
Mr Trump has struck a different tone to current US policy on some aspects of the multi-sided Syrian conflict, where the United States with allies Turkey and Saudi Arabia has backed some of the insurgents who have been fighting to topple Mr Assad for more than five years.
Mr Trump has questioned the wisdom of backing rebels, played down the US goal of getting President Assad to leave power, and noted that while he did not like him, "Assad is killing ISIS" with Iran and Russia. ISIS is an acronym for the so-called Islamic State.
"That's why for us it's still dubious whether he (Trump) can do or live up to his promises or not," Mr Assad said.
"That is why we are very cautious in judging him ... but let's say if he is going to fight the terrorists of course we are going to be [an] ally, natural ally with the Russians, with the Iranians," he added.
Damascus had long hoped it could win back international legitimacy as part of the international fight against so-called Islamic State, but the US has rejected that idea, viewing Mr Assad as part of the problem.
Mr Assad said he was ready to co-operate with Washington if it ended its policy of supporting rebels seeking to overthrow his government.
"Of course definitely if they are genuine, if they have the will ... Not co-operation between a foreign government and any faction within Syria," he said.
While Washington has provided significant support to the opposition, it has never matched the backing given to Mr Assad by Russia and Iran. The rebels have seen US policy as a betrayal of their revolt, with Washington focusing mostly on the fight against IS in the last two years.
The Syrian president said winning the war was the only option he had with defeat bringing the end of his country.
"We can say, you can win the war only when you restore stability in Syria. You cannot talk about winning the war as long as there is killing and destruction on a daily basis," Mr Assad said.
The war has shattered Syria into a patchwork of areas controlled by Mr Assad's state, rebels battling to topple him, a powerful Kurdish militia, and so-called Islamic State.
Hundreds of thousands of people have died and the war has created the world's worst refugee crisis.