World Bulletin / News Desk

North Korea will never completely give up its nuclear weapons, a top defector said ahead of leader Kim Jong Un's landmark summit with US President Donald Trump next month.

"In the end, North Korea will remain 'a nuclear power packaged as a non-nuclear state'," Thae told the South's Newsis news agency.

His remarks come ahead of an unprecedented summit between Kim and Trump in Singapore on June 12, at which North Korea's nuclear and missile programmes are expected to dominate the agenda.

North and South Korea affirmed their commitment to the goal of denuclearisation of the peninsula at a summit last month, and Pyongyang announced at the weekend it would destroy its only known nuclear test site next week.

South Korean President Moon Jae-in on Monday welcomed the announcement, calling it an "initial step in the complete denuclearisation of North Korea".

But North Korea has not made public what concessions it is offering, and the South's JoongAng Ilbo daily pointed out that it had only invited journalists to witness the operation at the Punggye-ri site.

"It is regrettable that North Korea did not invite nuclear experts to the destruction of the test site," it said in an editorial. "If North Korea has really decided to denuclearise, it has no reason not to invite them."

Pyongyang has said it does not need nuclear weapons if the security of its regime is guaranteed.

US Secretary of State Mike Pompeo, who has met Kim twice, said he was "convinced" the North Korean leader shared US goals, and promised security assurances and bountiful American investment in the isolated nation.

"Those are the kind of things that, if we get what it is the President has demanded -– the complete, verifiable, irreversible denuclearisation (CVID) of North Korea -– that the American people will offer in spades," Pompeo said on Fox News Sunday.