SEOUL • The United States is in behind-the-scenes talks with North Korea over a possible third summit and has proposed working-level negotiations that have been stalled since the second such meeting in February, South Korean President Moon Jae-in said yesterday.

Mr Moon, in written answers to questions from visiting foreign journalists, said there was no reason to talk of a stalemate just because there had been no official dialogue aimed at the denuclearisation of North Korea.

US President Donald Trump and North Korean leader Kim Jong Un held their second meeting in the Vietnamese capital of Hanoi in February but failed to reach a deal due to differences between US calls for denuclearisation and North Korean demands for relief from sanctions.

"Both sides have been engaged in dialogue in regard to a third summit," Mr Moon said. "It's noteworthy that the behind-the-scenes talks have been preceded by the mutual understanding of each other's position gained through the Hanoi summit."

The US had made a proposal for working-level talks, Mr Moon said, urging North Korea to return to the negotiating table "at the earliest date possible".

North Korea pursued nuclear and missile programmes for years in defiance of United Nations Security Council resolutions as well as UN and US sanctions.

Mr Moon has been an ardent champion of efforts to end the confrontation, vowing to play a mediator role in nudging North Korea into giving up its nuclear weapons in exchange for an end to sanctions and security guarantees.

The Hanoi breakdown was a blow for Mr Moon, who days before the summit offered to "ease the burden" of the US by providing concessions to the North through inter-Korean economic initiatives which he seeks to revive.

Mr Moon did not specify when and how the US proposal was made. But US Secretary of State Mike Pompeo on Sunday said a recent exchange of letters between Mr Trump and Mr Kim boosted hopes for a restart of talks, calling it a "very real possibility".

Also on Sunday, North Korea's official KCNA news agency said Mr Trump's letter had "excellent content" and that Mr Kim would "seriously contemplate" it.

US special envoy for North Korea Stephen Biegun, who led working-level talks ahead of the Hanoi summit, is visiting Seoul from today for meetings with South Korean officials before joining Mr Trump, who is due in South Korea this weekend.

Mr Trump is considering visiting the Demilitarised Zone (DMZ) separating the two Koreas, where Mr Kim and Mr Moon had their historic first summit last year, a South Korean official said.

The two Koreas are technically still at war after their 1950-53 conflict ended in a truce, not a treaty.

But a US official on Tuesday said Mr Trump had no plans to meet Mr Kim during his trip and declined to comment on whether Mr Trump would go to the DMZ.

Mr Trump wanted to travel to the DMZ during a 2017 visit to South Korea but heavy fog prevented it.

Mr Moon said: "The resumption of negotiations between North Korea and the United States will take it to the next level. I believe everything has now fallen into place for that to happen."

The Hanoi summit cast doubt on Mr Kim's commitment to denuclearise. There has been little progress since, with Pyongyang resuming limited testing of weapons and being aloof towards dialogue offers both from Washington and Seoul.

There is also a grey area over the denuclearisation of the "Korean peninsula", which, by North Korea's reckoning, includes the regional US nuclear umbrella protecting Japan and South Korea. The US, however, only wants North Korea to denuclearise.

Mr Moon said Mr Kim had told him he wanted to "finalise a denuclearisation process as soon as possible and to concentrate on economic development". The South Korean leader has called for the North to scrap the "passive stance" it has presented since the Hanoi summit and take action on its past promises. "By responding to the US proposal for working-level negotiations, it can also show its determination to denuclearise," he said.

Yesterday, North Korea denounced Mr Pompeo as an obstruction to nuclear negotiations, saying that his recent comments were "a manifestation of the most extreme hostile acts" against Pyongyang.

The top US diplomat had told reporters earlier this week that "some 80-plus per cent of the North Korean economy is sanctioned". He immediately corrected himself, saying he had misspoken and the figure applied to the effect of US sanctions on Iran, but the remarks were nonetheless deemed reckless by Pyongyang.

Hostile comments and actions by US policymakers were hampering top-level efforts to revive the stalled diplomacy, the North's Foreign Ministry spokesman said, so that it would be difficult to look forward to "the denuclearisation of the Korean peninsula".

REUTERS, AGENCE FRANCE-PRESSE