of sanctions. He stated that North Korea wanted 5 out of 11 sanctions originally imposed by the United Nations in 2016 and 2017 lifted; in exchange, Ri said that North Korea offered to "permanently and completely" dismantle its primary nuclear facility in Yongbyon, and that American experts would be allowed to observe. Ri also quoted North Korea as proposing to put in writing that the country would end all nuclear tests and long-range missile tests. He said that the North Koreans saw that no agreement could be made after the United States demanded one further measure in addition to destroying the Yongbyon nuclear facility. Lastly, Ri concluded that North Korea's proposal would not be changed. According to NK News, Vice Foreign Minister Choe Son-hui made the proposal to dismantle Yongbyon just before the talks collapsed, but the U.S. team walked out when Choe was unable to give details. News report NBC News reported that American negotiators had dropped their demand that North Korea provide a detailed inventory of its nuclear and missile programs on the second day of the summit. Nuclear scientist Dr. Siegfried Hecker claimed: "Yongbyon is the heart of North Korea's nuclear program, and if we are completely dismantling the Yongbyon nuclear facility, North Korea would never be able to make plutonium there again." Reactions and analysis Pre-summit Cheong Seong-chang, vice president of research planning at the Sejong Institute in South Korea, said: "After the first Trump–Kim summit, for 260 days, they did not waste their timeliness. Instead, they continuously finalized their negotiation strategies for the two leaders' agreement and terms for the next step to be discussed on the second Trump–Kim summit." BBC News believed that Kim Jong-un could have potentially learned from Vietnam's social, political and economic history during the second Trump-Kim summit. While the country has strict rules against political liberalization, it is fairly lax in their social, religious, and economic guidelines. Citizens were able to travel to neighboring countries often. Vietnam also pursued multi-front foreign policies so they would not be dependent on just one economy and built modern systems for banking and finance. According to the BBC, North Korea also learned from Vietnam's mistakes in the past regarding natural resources management and political unrest resolution. The BBC believed these are some cases North Korea could learn from Vietnam's practice to help them in improving their economy by attracting foreign investors and developing closer