If the Trump administration "corners us and unilaterally demands we give up nuclear weapons we will no longer have an interest in talks and will have to reconsider whether we will accept the upcoming DPRK-US summit", first vice foreign minister Kim Kye Gwan said in a statement carried by the official KCNA news agency.

Washington is pressing for Pyongyang's complete, verifiable and irreversible denuclearisation. But so far the North has not given any public indication of what concessions it is offering.

At a summit with the South's President Moon Jae-in last month, Kim Jong Un reaffirmed his commitment to the denuclearisation of the Korean peninsula.

But the phrase is a diplomatic euphemism open to interpretation on both sides.

"We already expressed our willingness for a denuclearised Korean peninsula and repeatedly declared that the US must end its hostile DPRK policy and nuclear threats as preconditions," the minister Kim said.

In the past, Pyongyang has demanded the withdrawal of the US troops stationed in the South to protect it from its neighbour, and an end to Washington's nuclear umbrella over its security ally.

Kim Kye Gwan also blasted US National Security Advisor John Bolton, who has spoken of a "Libyan model" for North Korean denuclearisation.

It was a "highly sinister attempt to enforce the fate of Libya and Iraq upon the DPRK," Kim said.

"I cannot suppress anger over this US move and it is doubtful whether the US really wants to improve ties with the DPRK through dialogue and negotiation."

The North has long said it needs nuclear weapons to protect itself against a US invasion. After giving up his atomic programme, Libyan leader Moamer Khadafi was killed in an uprising backed by NATO bombing.