Washington, DC and Pyongyang criticised for squandering 'rare opportunity' in the last two years to iron out a deal.

Kim Jong Un has made it clear there will "never be denuclearisation on the Korean Peninsula" if Washington adheres to "its hostile policy", as the North Korean leader's year-end deadline for the Trump government to restart negotiations elapsed.

Kim and US President Donald Trump met twice last year - in Hanoi and at the Korean Demilitarized Zone, the area dividing the two Koreas - but failed to reach an agreement that seemed imminent after the landmark 2018 Singapore talks.

The North Korean leader issued a year-end deadline to the Trump administration to get back to the negotiating table.

The US regarded the ultimatum as artificial and in his New Year's address following a four-day Worker's Party meeting in the North Korean capital Pyongyang, Kim made it clear there were no grounds for North Korea to be bound by a self-declared moratorium on testing nuclear bombs and intercontinental ballistic missiles (ICBMs).