Trump has pledged an "America First" policy of prioritising US interests above all else. He has put a focus on cracking down on undocumented immigration and said he will deploy the military to the border with Mexico.

But Trump has also cast himself as a peacemaker, AFP reported.

Earlier, Trump had vowed to end the Ukraine war immediately on taking office, raising expectations he would leverage aid to force Kyiv to make concessions to Russia, which invaded in February 2022.

But in unusually heated remarks about Russian President Vladimir Putin, for whom he has previously voiced admiration, Trump pointed to the state of Russia's economy and its heavy battlefield losses.

"He should make a deal. I think he's destroying Russia by not making a deal," Trump told reporters on his return to the Oval Office.

"He can't be thrilled he's not doing so well. I mean, he's grinding it out, but most people thought that war would have been over in about one week, and now you're into three years, right?" Trump said.

Trump said he was preparing to meet Putin. A summit between the two in his first term gained notoriety after Trump appeared to accept the Russian leader's word over that of US intelligence.

"I got along with him great," Trump said Monday. "I would hope he wants to make a deal."

Trump has also pointed to a Gaza ceasefire deal whose implementation began Sunday – a deal first proposed by his predecessor Joe Biden but pushed through after unusual coordination between the outgoing and incoming administrations.

"My proudest legacy will be that of a peacemaker and unifier. That's what I want to be -- a peacemaker and a unifier," he said in his inaugural address.

At an indoor rally where he signed executive orders, Trump welcomed the families of hostages still being held in Gaza, some holding pictures of their loved ones.