"Come on, what he was saying in context was that if North Korea lives up to the commitments that it made on denuclearization, then it would no longer be a threat," he said. "The test here will be what North Korea actually does to live up to the commitment that they made in Singapore that they say they still uphold and that now they need to fulfill."

Trump and Kim met in Singapore last month and produced a joint statement committing the North to the "complete denuclearization" of the Korean Peninsula in exchange for security guarantees from the US.

Officials from the two sides have held follow-on meetings to flesh out the deal amid criticism that Trump gave away too many concessions in return for a vague promise to dismantle the regime's nuclear weapons program.

Asked if he thinks North Korea is meeting its commitments, Bolton passed judgment to the US point man on North Korea, Secretary of State Mike Pompeo.

"I think that's what Secretary Mike Pompeo is doing in his meetings," he said. "He's got a very tough job. We're all trying to help him out. And he's going to work it through."

Trump tweeted shortly after returning from Singapore, "everybody can now feel much safer than the day I took office" and "there is no longer a Nuclear Threat from North Korea."

Two weeks later Pompeo sought to clarify the president's remarks, saying North Korea continues to pose a nuclear threat but that "for the moment, we have reduced the risk." (Yonhap)