"It did not directly mention the USA, but linked sanctions with hostile forces", said Shin Beom-chul, a senior fellow at the Asian Institute for Policy Studies in Seoul.
The new demands went far beyond the more incremental approach to denuclearisation that Washington had publicly touted ahead of the summit, and which is more in line with the strategy of President Moon.
Trump, speaking ahead of closed-door talks at the White House with Moon, said it "isn't the right time" for signing off on sanctions exemptions for inter-Korean projects, including the reopening of the Kaesong industrial facility and Mount Kumgang tourism site, which Moon and Kim agreed to during their third summit in September past year.
North Korean leader Kim Jong Un takes part in the 4th Plenary Meeting of the 7th Central Committee of the Workers' Party of Korea (WPK) in Pyongyang in this April 10, 2019, photo released April 11, 2019 by North Korea's Korean Central News Agency.
But Moon's plan to unveil details of such projects on March 1, right after the Hanoi summit, was scrapped and he is under pressure from opponents on the right.
According to analysts at NK News, a website that monitors North Korea, Pak helped oversee a process of "radical reform" in the economy that helped it survive sanctions. Unlike many other news organizations, we have not put up a paywall.
Noerpe added that there are good reasons for both Trump and Kim to offer Moon some movement, given the domestic challenges he faces.More news: House Passes Net Neutrality Bill, But Prospect Remains Dim
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Pyongyang wanted major sanctions relief in exchange for dismantling its Yongbyon nuclear facility.
The comments, reported by state media Thursday, represent Kim's first official, defiant response to the breakdown of the second U.S.
US President Donald Trump has emerged as an unlikely peacemaker in the Korean peninsula as he stages a determined effort to put Washington and Pyongyang on a historic path to reconciliation.
On top of being elected as the nominal head of state, Choe was also appointed as first vice chairman of State Affairs Commission (SAC), the North's highest decision making body - a position that was newly created after the North recently revised its Constitution.
Some reports have even suggested that one of Choe's sons is married to Kim Jong Un's powerful sister, Kim Yo Jong.
At a similar plenary session a year ago, Kim formally announced a "new strategic line" that focused on economic progress and improving North Koreans' lives, rather than the previous two-pronged approach of economic and nuclear weapons development.
Kim Jong-un has vowed to deliver a "serious blow" to hostile countries he accused of using sanctions to bring the regime "to its knees", according to the country's state media.