However a prosperous South Korea complicates the situation for the North, which may fear being swallowed up by Seoul economically if they reunify, as happened to the former East Germany, Cabestan said.
"Therefore. I am continuing for 1 year the national emergency with respect to North Korea declared in Executive Order 13466".
The pomp and circumstance looked geared towards showing off the major improvement in relations between the communist neighbours, along with China's important role in keeping North Korea on track.
Chinese state media outlets quoted Xi as hailing the warming friendship with Kim but included no mention of any specific discussions on making progress on the denuclearization of the Korean Peninsula.
After a series of key advances in North Korean missile and nuclear technology were matched with a heated war of words between the USA and North Korea last year, Kim reached out to US -backed South Korea for peace talks at the beginning of this year.
The limited numbers of reunions are vastly insufficient to meet the demands of aging relatives, who are mostly in their 80s and 90s, South Korean officials say.
The Cold War-era allies, which fought side-by-side against US-led United Nations forces and South Korea in the 1950-1953 Korean War, have sought to fix ties strained by Pyongyang's nuclear tests and Beijing's support of subsequent United Nations sanctions.
What is know has been pieced together from experts' reports and the North Korean state news agency KCNA.
It was reported to have been established in 2008 and has research facilities nearby for missile development as well as a tower that can support ballistic missiles.
A US official said on Wednesday that the site Trump referred to then was the Sohae Satellite Launching Ground, a major facility in the western part of the country that has been used for testing engines for long-range missiles.
Mr Kim also told Mr Xi he was willing to bolster the bilateral friendship and co-operation, it said.
The testing site in question is in Ch'olsan County, North Pyongan province, and is sometimes is referred to as the Sohae Satellite Launching Ground, according to an administration official.
"The United States got a bad deal in Singapore", Abraham Denmark, former USA deputy assistant secretary of defense for East Asia, told the House Foreign Affairs Committee subpanel on Asia and Pacific issues.
And as far as the South Koreans are concerned, the last thing they want is probably a North Korea that is secretly retaining its nuclear capabilities and undergoing rapid economic growth at the same time. If not, verification will have to rely on DNA analysis according to very strict protocols observed by the US military for missing soldiers.
"We need to closely watch North Korea's steps toward denuclearisation".
Asked on Wednesday if North Korea had done anything toward denuclearisation since the summit, US Defence Secretary Jim Mattis told reporters: "No, I'm not aware of that ... obviously, it's the very front end of a process".
He added: "The detailed negotiations have not begun. I wouldn't expect that at this point". The official described it is as a major center that has been used for testing engines for long-distance missiles. "In fact, it was actually four of their big test sites", he said.
It also declared that the "DPRK commits to work toward complete denuclearization of the Korean Peninsula".