WASHINGTON (BLOOMBERG) - The White House distanced itself from the hardline North Korea stance of President Donald Trump's top security adviser, indicating his administration is committed to keeping next month's summit with Mr Kim Jong Un on track.

Press Secretary Sarah Huckabee Sanders told reporters on Wednesday (May 16) that she was "not aware" of the administration advocating a so-called Libya model, in which North Korea would quickly ship its nuclear weapons programme to the US.

North Korea had earlier attacked National Security Adviser John Bolton for trying "to force our unilateral nuclear abandonment" and threatened to walk away from the June 12 summit in Singapore.

"I haven't seen that as a specific thing," Ms Sanders said. "This is the President Trump model. He is going to run this the way he sees fit."

The decades-old debate over how and when North Korea gives up its nuclear weapons programme has reemerged in the run-up to Mr Trump's first-of-its-kind meeting with Mr Kim.

While Mr Kim has agreed to discuss "denuclearisation", he wants a phased approach and an end to Mr Trump's "maximum pressure" campaign of international sanctions.

"The fact that the Trump administration seems to be showing some flexibility is a welcome development because its posture on denuclearisation thus far has been too inflexible to lead to a meaningful deal with North Korea," said Mr Mintaro Oba, a former US State Department official who worked on North Korean issues.

"The worst thing the White House could have done was to escalate the situation."

Financial markets shrugged off concern that talks between the US and North Korea would be derailed. South Korea's benchmark Kospi index was little changed as 12.16pm in Seoul.

Asked later on Wednesday if the summit would go ahead, Mr Trump said, "We'll have to see."

He said that the administration was still pursuing denuclearisation and that US officials hadn't yet been notified of North Korea's concerns, which were expressed in a statement by First Vice Foreign Minister Kim Kye Gwan.

"We haven't been notified at all," Mr Trump said.

The Libya approach described by Mr Bolton is particularly controversial in North Korea because leader Muammar Gaddafi was killed by Nato-backed rebels two years after the last remnants of the programme were delivered.

"World knows too well that our country is neither Libya nor Iraq, which have met miserable fate," Mr Kim Kye Gwan said.

Both Mr Bolton and US Secretary of State Mike Pompeo have said the US wants North Korea's "complete, verifiable, irreversible denuclearisation".

Mr Pompeo, who has travelled to Pyongyang and met with Mr Kim twice in the past few months, has also indicated that the US may initially accept a deal that puts the American homeland out of danger.

"Make no mistake about it: America's interest here is preventing the risk that North Korea will launch a nuclear weapon into LA or Denver or into the very place we're sitting here this morning," Mr Pompeo told Fox News Sunday.