Kim Sung-han, professor of worldwide relations at Korea University, said Trump will have difficulty accepting any conditions from North Korea, partly because he had been so critical of the Iran nuclear deal. North Korea denied any involvement in the attack on the ship and on Sony Pictures. But Kim also said he was unsure whether he could trust the United States over its promise to end hostile policies against North Korea and provide security assurances if the country does abandon its nuclear weapons, according to Moon.
In previous, failed talks, North Korea said it could consider giving up its arsenal if Washington removed its troops from South Korea and withdrew its so-called nuclear umbrella of deterrence from South Korea and Japan.
The two diplomats have crossed paths several times in the past, especially during the six-party negotiation process.
Also in the group were Allison Hooker, the National Security Council's expert on Korea, and an unnamed Defense Department official.
Mr Kim and Mr Moon held talks in the demilitarised zone separating their two nations on Saturday in a scramble to salvage the summit. The second was held with no prior notice and only announced hours after it had concluded.
While both Trump and Kim have appeared eager to hold the summit, the two sides have remained far apart on the key issue of denuclearization, with North Korea rejecting USA demands for it to unilaterally abandon a nuclear weapons program that now threatens the United States.
By the weekend, Mr. Trump was singing a different tune, tweeting, "I truly believe North Korea has brilliant potential and will be a great economic and financial Nation one day".
According to the State Department, the US team met with North Korean officials at the same DMZ site, the village of Panmunjom. Aides are cautiously optimistic this time will be different, even as they continue to express private misgivings about the compressed timeline to arrange the meeting.More news: Historic day! The RTE Repeal referendum exit poll has just been released
A former military spy chief, Kim Yong Chol has been a central player in the recent thaw in relations between North Korea and South Korea, as well as the United States.
In other news, speculators trimmed their net long position in COMEX gold by 3,800 contracts to 27,527 contracts in the week to May 22, U.S. Commodity Futures Trading Commission (CFTC) data showed on Friday.
USA officials have talked about a comprehensive one-shot deal in which North Korea eliminates its nukes first and receives rewards later. He would be the most senior North Korean official to visit the United States in 18 years. US financial markets will be closed Monday for Memorial Day.
"It's a good thing to have him on board", a former senior South Korean official who has worked with him told Reuters.
Even critics of Trump's speedy approach to the talks, talks of a potential Nobel Prize, and subsequent return to vows of the use of military force if North Korea doesn't comply with US terms, said they expect the talks to move forward in order to avoid losing ground.
Libyan dictator Moammar Qaddafi agreed in 2003 to give up his weapons of mass destruction, including nuclear arms, in return for sanctions relief.
"What is unclear to Chairman Kim Jong Un is not the will for denuclearisation, but the concern that if (North Korea) denuclearises, whether the United States can end hostile relations and guarantee the security of the (Kim) regime", Mr Moon said.
Moon said on Monday there could be more impromptu talks between the two Koreas in the lead-up to the summit. Trump, in turn, signaled by Saturday that preparations for a U.S.