Pompeo: 'ways to go' before NKorea meets denuke vow

US Secretary of State Mike Pompeo says North Korea is far from living up to its pledge to denuclearize and remains in violation of numerous UN Security Council resolutions.

Speaking today before he attends an Asian security forum with North Korea's foreign minister, Pompeo told reporters in Singapore there was "still a ways to go before" achieving the goal of ridding the North of its nuclear weapons.

Pompeo's comments came after the White House announced yesterday that President Donald Trump received a new letter from North Korean leader Kim Jong Un and responded quickly with a letter of his own.

The correspondence, following up on their Singapore summit in June, came amid fresh concerns over Pyongyang's commitment to denuclearisation despite a rosy picture of progress painted by Trump.

Pompeo has taken the lead in negotiations with the North, having traveled to Pyongyang three times since April and accompanied Trump to the summit, will be in the same room on Saturday as his North Korean counterpart at the Association of South East Asian Nations annual regional forum.

A separate meeting between the two was a possible, but not confirmed, according to State Department officials.

"Chairman Kim made a commitment to denuclearize," Pompeo told reporters accompanying him to Singapore from Kuala Lumpur, Malaysia.

"The world demanded that (he) do so in the UN Security Council resolutions. To the extent they are behaving in a manner inconsistent with that, they are in violation of one or both the UN Security Council resolutions, we can see we still have a ways to go to achieve the ultimate outcome we're looking for."