BEIRUT • Syria will ally itself with United States President- elect Donald Trump if his administration is genuinely committed to fighting ISIS militants, President Bashar al-Assad said.

"Let's say, if he is going to fight the terrorists, of course, we are going to be an ally, a natural ally, in that regard, with the Russians, with the Iranians, with many other countries who want to defeat the terrorists," Mr Assad said.

He was responding to a question on Mr Trump's willingness to work with Syria in the fight against the Islamic State in Iraq and Syria during an interview with Portuguese broadcaster RTP on Tuesday.

Yet, he said he was still doubtful about whether Mr Trump can do that and " live up to his promises", given the "forces within the administration" and the "mainstream media that opposed" the President-elect.

During his campaign, Mr Trump said he knows more about ISIS than the military, and that he has a secret plan to defeat the group. He said he would give his top generals 30 days to come up with a plan.

ISIS declared a caliphate straddling parts of Syria and Iraq after capturing Mosul, Iraq's biggest northern city, in June 2014.

Since then, extremists linked to the group have proliferated and murdered hundreds in Ankara, Beirut, Brussels and Paris as well as in Iraq, Syria and elsewhere.

The US is leading a campaign against ISIS militants in Iraq and Syria, but the Assad government considers the airstrikes illegal because they are not coordinated with Syria's efforts.

BLOOMBERG