(CNN) Donald Trump warned in an interview Tuesday that Hillary Clinton's policies as president to address the Syrian conflict would lead to World War III, arguing the Democratic nominee would draw the US into armed confrontation with Russia, Syria and Iran.

"What we should do is focus on ISIS. We should not be focusing on Syria," Trump told Reuters on Tuesday morning at his resort in Doral, Florida. "You're going to end up in World War III over Syria if we listen to Hillary Clinton."

The Republican nominee, who has called for a rapprochement with Russia in order to jointly combat ISIS, argued that his Democratic rival's calls for taking a more aggressive posture in Syria to bring the conflict there to an end and combat ISIS will only draw the US into a larger war. Trump's remarks come as he trails Clinton in most national and key battleground state polls just two weeks from Election Day.

"You're not fighting Syria anymore, you're fighting Syria, Russia and Iran, all right? Russia is a nuclear country, but a country where the nukes work as opposed to other countries that talk," he said.

Trump has not laid out a clear strategy for combating ISIS or addressing the globally destabilizing conflict in Syria, which has killed hundreds of thousands and pushed millions more to flee their homes. He has suggested the US should allow ISIS, anti-government rebels and the Syrian government to fight it out and more recently has focused on joining forces with Russia -- which has aided the Syrian regime in the bombing of civilians and US-allied rebels -- to combat ISIS.

"Assad is secondary, to me, to ISIS," Trump told Reuters of the Syrian President Bashar al-Assad, whom US officials have argued must step down.

Clinton has called for establishing a no-fly zone over Syria to help bring the five-year civil war to an end, a proposal top Republicans in Congress have championed, which President Barack Obama and others have opposed due to the risk of entering into conflict with Russia. A US-enforced no-fly zone would mean the US could shoot down a Russian jet should it enter Syrian airspace.

Clinton addressed those concerns in the final presidential debate, arguing that it would "save lives and hasten the end of the conflict," while cautioning that "this would not be done just on the first day."

"This would take a lot of negotiation and it would also take making it clear to the Russians and the Syrians that our purpose is to provide safe zones on the ground," Clinton said during the debate earlier this month. "I think we could strike a deal and make it very clear to the Russians and Syrians that this was something that we believe the best interests of the people on the ground in Syria. It would help us in the fight against ISIS."

Trump has additionally called for establishing safe zones in Syria to protect civilians -- as has Clinton -- which could also put the US in conflict with the Syrian government or Russia should they oppose the policy.

The Clinton campaign later Tuesday pushed back against Trump's rhetoric.

"National security experts on both sides of the aisle have denounced Donald Trump as dangerously ill-prepared and temperamentally unfit to serve as commander-in-chief," Clinton spokesman Jesse Lehrich said. "Once again, he is parroting Putin's talking points and playing to Americans' fears, all while refusing to lay out any plans of his own for defeating ISIS or alleviating humanitarian suffering in Syria. Moreover, this incendiary attack is aimed at a policy that his own running mate, Mike Pence, strongly supports."

While Clinton has accused Trump of being Putin's "puppet," Trump knocked Clinton for her criticism of the Russian strongman, asking, "How she is going to go back and negotiate with this man who she has made to be so evil."

And just two days after he tied the successful enactment of his agenda as president to the election of Republican majorities in Congress, Trump also returned to his more typical complaints of a lack of Republican unity weighing down his candidacy.

"If we had party unity, we couldn't lose this election to Hillary Clinton," he told Reuters.

That complaint didn't put Trump in more of a bipartisan mood, though, as the Republican nominee also told Reuters he would not consider putting any Democrats in his cabinet -- a departure from recent presidents, who have sought to post at least one member of their rival party in a top administration post.