US opposes incremental denuclearisation of North Korea: Envoy

A top US envoy said Monday Washington's goal is the complete denuclearisation of North Korea by the end of Donald Trump's first term, insisting it will not settle for incremental disarmament.

"We are not going to do denuclearisation incrementally," said Stephen Biegun, the special US envoy for North Korea.

While stressing he was not bound by an artificial calendar, Biegun said the administration wanted to accomplish the complete and verified denuclearisation of North Korea by the end of Trump's term in January 2021.

The US side has included North Korea's chemical and biological weapons in the negotiations with Pyongyang.

The envoy said there could be no comprehensive agreement with the North without agreement on each point, adding that there was "complete unity" in the administration on that approach.

Speaking at a conference organised by the Carnegie Endowment for International Peace, Biegun said progress had been made despite the failure of Trump's second summit with North Korean leader Kim Jong Un, held in Hanoi last month.

"The door remains open" for further negotiations, he said, adding, however, that "the North Koreans have to be fully invested."