WASHINGTON - President Donald Trump on Thursday (May 17) said he was "willing to do a lot" and offer North Korean leader Kim Jong Un "protection" if he were to make an agreement at the two leaders' upcoming summit in Singapore on June 12.

"He will get protections that are very strong," Mr Trump told reporters at an Oval Office meeting with visiting Nato secretary-general Jens Stoltenberg. "The best thing he could do is make a deal."

Mr Trump said he is not considering a so-called Libya model for dismantling North Korea's nuclear weapons programme.

The US "decimated" Libya, the American President said, but that's not what he has in mind for North Korea.

"That model will take place if we don't make a deal, most likely," he warned.

"But if we do, I think Kim Jong Un will be very happy. We're willing to do a lot."

"We never said to Gaddafi, 'Oh, we're going to give you protection, we're going to give you military strength, we're going to give you all of these things,'" he said.

Mr Trump said instead that a deal with the US would allow Mr Kim to stay in power and that the country would be rich.

"This would be... something where he'd be there, he'd be in his country, he'd be running his country, his country would be very rich," Mr Trump said.

"His people are tremendously industrious. If you look at South Korea, this would be really a South Korean model in terms of their industry. In terms of what they do, they're hardworking, incredible people."

The US is willing to provide security guarantees, Mr Trump added, but he declined to address the possibility of scaling back American troops in South Korea to appease the North.

Pyongyang has long viewed the 28,500-strong troop presence as a threat to the regime.

North Korea threw the summit into doubt on Wednesday (May 16), saying it would reconsider meeting if the US insisted on demanding nuclear disarmament.

Reports say the White House was taken by surprise. Analysts are saying it was a wake-up call for Mr Trump, who in recent weeks has been praising Mr Kim.

The US President suggested that the North Korean leader may have been influenced by China's President Xi Jinping.

"A few weeks ago out of nowhere Kim went to China to say hello a second time to President Xi," Mr Trump said, apparently referring to Mr Kim's May 7 to 8 meeting with Mr Xi in Dalian.

"It could very well be that he (Xi Jinping) could be influencing Kim, but we'll see," Mr Trump said.

South Korea's JoongAng Ilbo, citing a government source, reported on Friday (may 18) that Mr Xi told the North Korean leader during their second summit that Beijing has his back even if the Trump-Kim summit fails.

"The two leaders particularly pledged China's active support in North Korea's politics, economy and diplomacy, regardless of the outcome of the North-U.S. summit," the source told JoongAng Ilbo.

America's new National Security Advisor John Bolton raised eyebrows when he suggested in late April that the Libya model could be used as a model for the disarmament of North Korea.

In the Libya case, its leader Muammar Gaddafi shipped all his nuclear material out of the country in 2003, but eight years later in 2011, was overthrown with the help of Nato forces and eventually met a violent death at the hands of a mob.

Mr Trump said on Thursday the Libyan model of packing up the weapons of mass destruction facilities and shipping them to the US was a much different deal.

In a statement issued on Wednesday, North Korea's Vice Foreign Minister Kim Kye Gwan said Bolton's suggestion of the Libya model was " a manifestation of awfully sinister move" to impose on North Korea the destiny of Libya or Iraq, which had been collapsed due to "yielding the whole of their countries to big powers".

When asked about the Singapore summit, Mr Trump said there had been no official word from North Korea to indicate it was off.

Preparations were moving ahead, he said.

"As of this moment North Korea is actually talking to us about timings and everything else as if nothing happened," Mr Trump added.

"If the meeting happens, it happens and if it doesn't, we go on to the next step."