Donald Trump could be a "natural ally" alongside Russia and Iran if he stands by his pledge to fight "terrorists," Syrian President Bashar al-Assad has said.

Assad made the comments to Portuguese state television in his first public reaction to Trump's election victory last week. He added that he was unsure if the US President-elect would keep his word to intensify the fight against jihadists.

"We cannot tell anything about what he's going to do, but if... he is going to fight the terrorists, of course we are going to be ally, natural ally in that regard with the Russian, with the Iranian, with many other countries," Assad told RTP state television.

Over the course of the election campaign, Trump promised to "bomb the hell out of Isis [the Islamic state]" and said he would give his generals 30 days to devise a plan to defeat the terror organisation.

When questioned about Trump's pledge to crack down on the group, Assad said: "I would say this is promising, but can he deliver?

"Can he go in that regard? What about the countervailing forces within the administration, the mainstream media that were against him? How can he deal with it?" he said.

"That's why for us it's still dubious whether he can do or live up to his promises or not.

"That's why we are very cautious in judging him, especially as he wasn't in a political position before," added Assad.

Bashar al-Assad
Syrian President Bashar al-Assad gestures during an interview in the capital Damascus on 11 February 2016 (file photo) Joseph Eid/AFP/Getty Images

Speaking after he clinched the White House, Trump told the Wall Street Journal (WSJ) that he has held "an opposite view of many people" when it comes to Syria, suggesting a stronger focus on combating Isis than getting rid of Assad.

"My attitude was you're fighting Syria, Syria is fighting Isis, and you have to get rid of Isis," said Trump. "Russia is now totally aligned with Syria, and now you have Iran, which is becoming powerful, because of us, is aligned with Syria. ... Now we're backing rebels against Syria, and we have no idea who these people are." He added that if the US attacks Syria, it will "end up fighting Russia."

Assad also accused the US of meddling in the affairs of other nations and warned Washington that it is neither the "police" nor the "judge of the world."

Since his election victory, Trump has spoken to Russian President Vladimir Putin, with the pair agreeing to combat "global enemy number one" – international terrorism and extremism.