SEOUL (THE YOMIURI SHIMBUN/ASIA NEWS NETWORK) - United States President Donald Trump has told North Korean leader Kim Jong Un that if Mr Kim presents a proposal that is a little more advanced than what he had put forward at their February meeting in Hanoi, Vietnam, the US will take "appropriate measures", the Yomiuri Shimbun has learnt.
According to a source close to the trilateral talks between Japan, the US and South Korea, the "appropriate measures" are expected to include the setting up liaison offices in both the US and North Korea as well as providing economic assistance for humanitarian purposes.
The two leaders discussed the North Korean nuclear issue at their third meeting on June 30 at the inter-Korean truce village of Panmunjom, which lies along the military demarcation line.
At their Hanoi talks, Mr Kim spoke of dismantling the North's nuclear facilities in Yongbyon, in the north-western part of the country. Mr Trump is said to have demanded more, including denuclearisation measures for uranium enrichment facilities and other steps, which could be described as a "Yongbyon plus".
The establishment of liaison offices is seen as a stepping stone towards the opening of embassies once the US and North Korea achieve normalisation of their diplomatic relations, and could provide the safety assurances for the North Korean regime that Pyongyang has demanded.
At the Panmunjom talks, the source said, Mr Kim insisted that a "phased, simultaneous and parallel denuclearisation" should be done, stating: "We are definitely prepared to dismantle Yongbyon. It is not a desirable way to try to achieve denuclearisation in a day."
It is believed that there have been no major changes from past arguments on the subject of denuclearisation.
In addition, Mr Kim seems to have sought an assurance for preserving the North's regime by saying that "the United States should abandon its hostile policies".
According to the source, Mr Trump suggested to Mr Kim that they hold their fourth summit this year, saying: "Let's meet again sometime this year and talk frankly."
While Mr Kim's reaction is unclear, the source said that the next summit is "likely to be held later this year".
The "Yongbyon plus" is believed to include US demands for denuclearisation measures at secret facilities such as a uranium enrichment facility at Kangsong in the suburbs of Pyongyang and a missile plant in Sanumdong, according to media reports.
The source described these secret facilities as the "final bargaining chips" for Mr Kim. Thus, he cannot easily put them on the negotiating table. Therefore, his response to the US approach will be a litmus test by which Mr Trump can determine Mr Kim's seriousness about denuclearisation.