WASHINGTON — The United States is prepared to offer North Korea security assurances and bountiful private investment if it makes the strategic choice to give up its nuclear weapons, US Secretary of State Mike Pompeo pledged Sunday.

The US price for normalisation -- complete, verifiable and irreversible denuclearization -- is one Pyongyang has never before been willing to pay, seeing nuclear weapons as the ultimate guarantee of the regime’s survival.

But both countries have been on charm offensives ahead of the summit June 12 in Singapore between Donald Trump and Kim Jong Un, the first ever between a sitting US president and a North Korean leader.

On Saturday, North Korea said it will destroy its nuclear test site later this month -- a gesture Trump quickly hailed as "very smart and gracious."

Pompeo, who has met twice with Kim, described him as well-informed and attuned to western media coverage, a leader "who knows his brief" and what he wants to achieve.

The secretary said he was "convinced" Kim shared US goals.

"We will have to provide security assurances, to be sure," Pompeo said on Fox News Sunday. "This has been the trade-off that has been pending for 25 years. No president has ever put America in a position where the North Korean leadership thought that this was truly possible."

"Our eyes are wide open with respect to the risks, but it is our fervent hope that Chairman Kim wants to make a strategic change," he said.

If Kim makes such a change, he said, "President Trump is prepared to assure that there’s going to be a successful transition."

Energy, infrastructure, meat

Pompeo dangled the prospect of a gusher of US investment in North Korea, with upgrades in energy, infrastructure, technology and agriculture, if a deal is struck.

"This will be Americans coming in...to help build out the energy grid -– they need enormous amounts of electricity in North Korea; to work with them to develop infrastructure, all the things that the North Korean people need, the capacity for American agriculture to support North Korea so they can eat meat and have healthy lives," he said.

"Those are the kind of things that, if we get what it is the President has demanded – the complete, verifiable, irreversible denuclearization of North Korea – that the American people will offer in spades."

In a separate television interview, US National Security Advisor John Bolton cautioned, however, that denuclearisation has to be accomplished "before the benefits start to flow."

He said that means the elimination of North Korea uranium enrichment facilities and the dismantling of its nuclear weapons arsenal.

"North Korea has a very extensive programme. It won’t be easy to do," Bolton said on ABC’s "This Week." "They’ll have to reveal all locations. Open inspections. The deconstruction of the nuclear weapons, I think, will be by the United States with perhaps assistance from others."

He suggested that could be done at the US nuclear weapons facilities at Oak Ridge, Tennessee.

Bolton said the US side also will discuss not just North Korea’s nuclear and missile programmes but its chemical and biological weapons arsenal as well.

"I don’t think the president has stars in his eyes," Bolton said. "What we need to see from Kim Jong Un is that he and the entire North Korean regime have made a strategic decision that they’ll be better off without weapons of mass destruction."

The summit will give Trump an early chance "to size Kim Jong Un up and see if the commitment is real," he said. — AFP