Washington, May 13 (PTI) US President Donald Trump sees the chance of a breakthrough in his meeting with North Korean leader Kim Jong-un in Singapore on June 12, his top National Security Advisor said today, but noted that he is aware of the challenges ahead.

Trump has said that his goal is "permanent, verifiable, and irreversible denuclearisation" of the Korean Peninsula, John Bolton told ABC.

The president has threatened to walk out of the meeting with Kim if he does not get a desired result, the NSA said.

"I think the president is very optimistic because he sees the chance of a breakthrough, but I don't think he had stars in his eyes over this," he said.

Bolton appeared on Sunday talk shows, during which the June 12 meeting between Trump and the North Korean leader dominated the proceedings.

"I think what we need to see from Kim is that he and the entire North Korean regime have made a strategic decision that they will be better off without weapons of mass destruction.

"One advantage of having this meeting between president Trump and Kim Jong-un, so soon without months and months and months of preparation is that president Trump will be able to size Kim Jong on up and see whether the commitment is real," he said.

Denuclearisation is absolutely at the core of it, Bolton said when asked what is non-negotiable.

"It means not just the nuclear weapons. North Korea has previously agreed several times, in fact, to give up at uranium enrichment and plutonium reprocessing capabilities.

"We've got the ballistic missile issue is on the table. We've got to look at chemical and biological weapons. There are a range of things to discuss. So that is really whether a Kim Jong-un will come through on this," Bolton said.

"This the reason why the president is both optimistic but realistic at the same time," Bolton told the Sunday talk show.

Permanent, verifiable, and irreversible denuclearization of the Korean Peninsula "has to happen" before the "benefits" start to flow, he said.

"The objective for North Korea is to see whether they want to become a normal nation," he said.

The US wants to see the denuclearisation process so completely underway that it's irreversible, Bolton said.

"The implementation of the decision means getting rid of all the nuclear weapons, dismantling them, taking them to Oak Ridge, Tennessee.

"It means getting rid of the uranium enrichment, plutonium reprocessing capabilities. That means addressing the ballistic missile issue. A lot of things like. North Korea has a very extensive programme. Nobody believes that this is a easy to do. It's going to require some discussion with North Korea," the NSA said.

Bolton asserted that the North Koreans would have to reveal all of their locations.

"They're going to have to allow open inspection. The International Atomic Energy Agency will have a role. In the actual deconstruction of the nuclear weapons will be by the United States perhaps with the assistance from others because that's not really in the IAEA's remit. We hope to do it very quickly," Bolton said.

Responding to a question, Bolton said he does not think that anybody believes that they are going to sign the complete the ending of the nuclear program in one day, "But we are also very much interested in operationalizing the commitment as quickly as possible and that is in North Korea's interest".

It is entirely in North Korea's hand when they want the benefits to flow or the sanctions to be lifted, he said.

"If they want to see opening to the rest of the world, if they want to become a normal nation like South Korea, the quicker they denuclearize the quicker that will come.

"If he wants to be a normal nation, if he wants to have normal relations with the rest of the world, if he wants to trade and investment to be possible for his desperately poor country, this is the path to do it. Nuclear weapons don't make North Korea's safer. They don't make it more prosperous," Bolton said.

The Trump administration, he said, is prepared to open the trade and investment with North Korea as soon as it can.

"We need to see implementation and I don't think the present policy is going to change until that happens," he said.

Bolton said the key point here is that the president's going to make the decision when he sits down with Kim Jong-un on just what exactly the North Korea is up to and he'll size him up.

(This is an unedited and auto-generated story from Syndicated News feed, LatestLY Staff may not have modified or edited the content body)