Talks to continue:North Korea's leader Kim Jong-un, centre, arriving for a ceremony at the Presidential Palace in Hanoi on Friday.AFPMANAN VATSYAYANA  

South Korea will work with the U.S. and North Korea to ensure they reach agreement on denuclearisation, the South’s President said on Friday, a day after talks between the U.S. and North Korean leaders collapsed over sanctions.

A second summit between U.S. President Donald Trump and North Korean leader Kim Jong-un, in Vietnam, was cut short after they failed to reach a deal on the extent of sanctions relief North Korea would get in exchange for steps to give up its nuclear programme.

South Korea’s President Moon Jae-in has been an active supporter of efforts to end confrontation on the Korean peninsula, meeting Mr. Kim three times last year and trying to facilitate his nuclear negotiations with the U.S.

“My administration will closely communicate and cooperate with the U.S. and North Korea so as to help their talks reach a complete settlement by any means,” Mr. Moon said in a speech in the South Korean capital, Seoul.

Joint tourism projects

Mr. Moon also said South Korea would consult the U.S. on ways to resume joint projects with the North, including tourism development at Mount Kumgang and the Kaesong industrial complex, both in North Korea.

The Hanoi summit came eight months after Mr. Trump and Mr. Kim met for the first time in Singapore and agreed to establish new relations and peace in exchange for a North Korean commitment to work toward complete denuclearisation of the Korean peninsula.

Mr. Trump said two days of talks had made good progress but it was important not to rush into a bad deal. He said he had walked away because of unacceptable North Korean demands.

“It was all about the sanctions,” Mr. Trump told a news conference after the talks were cut short. “Basically, they wanted the sanctions lifted in their entirety, and we couldn’t do that.”

On Friday, Mr. Trump tweeted that the negotiations with Kim were “very substantive” and that “we know what they want and they know what we must have,” but he gave no other details about any next steps. “Relationship very good, lets see what happens!” he wrote.

‘Biggest step so far’

However, North Korean Foreign Minister Ri Yong Ho told a news conference after Mr. Trump left Hanoi that North Korea had sought only a partial lifting of sanctions “related to people’s livelihoods and unrelated to military sanctions.”

He said North Korea had offered a realistic proposal involving the dismantling of all of its main nuclear site at Yongbyon, including plutonium and uranium facilities, by engineers from both countries.

“This is the biggest denuclearisation step we can take based on the current level of trust between the two countries,” Mr. Ri said.

North Korean Vice-Foreign Minister Choe Son Hui told the briefing she had the impression that Mr. Kim “might lose his willingness to pursue a deal” after the U.S. side rejected a partial lifting of sanctions in return for destruction of Yongbyon, “something we had never offered before.”

Speaking to South Korean media later on Friday, Ms. Choe appeared more pessimistic about chances for progress.

“Having conducted the talks this time, it occurs to us that there may not be a need to continue,” she said, adding that North Korea had taken “many steps” to try to reach a deal.

“We’re doing a lot of thinking,” she said while adding, the situation would change “if our demands can be resolved.”

But despite the doubt that Ms. Choe raised, both sides have indicated they want to maintain the momentum and press on.

“We are anxious to get back to the table so we can continue that conversation that will ultimately lead to peace and stability, better life for the North Korean people, and a lower threat, a denuclearised North Korea,” U.S. Secretary of State Mike Pompeo said in Manila.

Mr. Kim, who is due to leave Vietnam on Saturday, also expressed gratitude to Mr. Trump for putting in efforts to get results, state KCNA news agency said.

The United Nations and the U.S. ratcheted up sanctions on North Korea when the reclusive state conducted repeated nuclear and ballistic missile tests in 2017, cutting off its main sources of hard cash.

‘Need full commitment’

The U.S. has demanded North Korea’s complete, verifiable and irreversible denuclearisation before sanctions can be lifted. North Korea has denounced that position as ”gangster like.”

The U.S. official said North Korea had proposed closing part of its Yongbyon nuclear complex in exchange for the lifting of all U.N. sanctions except those directly targeting their weapons of mass destruction programmes.

The U.S. side said “that wouldnt work”, he said.

“The dilemma that we were confronted with is the North Koreans at this point are unwilling to impose a complete freeze on their weapons of mass destruction programmes,” said the official, who declined to be identified. “So to give many, many billions of dollars in sanctions relief would in effect put us in a position of subsidising the ongoing development of weapons of mass destruction,” said the official, who spoke on condition of anonymity.

Analysts estimate North Korea may have a nuclear arsenal of 20 to 60 weapons, which, if fitted to its intercontinental ballistic missiles, could threaten the U.S mainland.