As prospects for a historic summit next month between the two leaders dimmed, Trump told reporters that if the meeting were to go ahead successfully, Kim "will get protections that will be very strong."

"He'd be in his country and running his country. His country would be very rich."

But the pledge came barbed with a warning that if talks fail, Kim could suffer the same fate as Libya's Moamer Kadhafi, who was overthrown by rebels and murdered.

Trump's comments came as Pyongyang appeared to cool to the idea of the sit-down in Singapore on June 12, blaming US demands for "unilateral nuclear abandonment."

Trump suggested Kim's about-face may have been at the behest of Chinese leader Xi Jinping.

"It could very well be that he's influencing Kim Jong Un," Trump said, citing a recent meeting between the pair, their second in a month's time. "We'll see what happens."

After months of photo-ops and diplomatic backslapping, a North Korean official was quoted as saying the summit may not go ahead.

The official also groused about Trump's National Security Advisor John Bolton, who referred to Libya as a model for denuclearization.

In 2003, Kadhafi agreed to the elimination of his country's nuclear program and chemical weapons arsenal to gain sanctions relief.

But Trump, and Pyongyang, appeared to zero in on what happened a decade later following the Libyan revolution, when NATO-backed rebels ousted the government and killed Kadhafi.

"The Libyan model isn't a model that we have (in mind) at all when we're thinking of North Korea," Trump said while sitting at arm's length from Bolton in the Oval Office.

"If you look at that model with Kadhafi, that was a total decimation. We went in there to beat him," Trump said.

"Now, that model would take place if we don't make a deal, most likely," he warned Pyongyang.

"But if we make a deal, I think Kim Jong Un is going to be very, very happy."