"'Kim Jong Un says North Korea will not make or test nuclear weapons, or give them to others - & he is ready to meet President Trump anytime, '" Trump tweeted, apparently citing a PBS News Hour report on Kim's New Year's address earlier in the day.
"His overarching message was confident, normal, sophisticated. reminiscent of the feel as the Singapore summit setting, wearing a suit and tie", said Duyeon Kim, an adjunct fellow at the Center for a New American Security.
In the speech, which stood in stark contrast to last year's address - which saw him order the mass production of nuclear warheads and ballistic missiles - Kim said himself for the first time that the North had "declared that we would no longer produce, test, use or spread our nuclear arsenal" and urged "corresponding measures" from Washington.
There was no immediate reaction from the US State Department, but South Korea's presidential office welcomed Kim's speech, saying it carried his "firm will" to advance relations with Seoul and Washington.
The North Koreans want a different relationship with the US before denuclearizing - such as through a peace treaty, but the USA wants North Korea to denuclearize before any such step.
A rapid sequence of developments followed, with athletes and a senior delegation led by Kim's powerful sister going to the Pyeongchang Games in February, before Kim met Chinese President Xi Jinping in Beijing ahead of the Singapore summit with Trump. Trump wrote quoting PBS News Hour.
Over the weekend, the North Korean leader sent a personal letter to President Moon Jae-in in what appeared to be a friendly gesture, expressing his intent to work together with South Korea to resolve the denuclearization issue.
However, Kim's statement could prove problematic if there's ongoing evidence the North's nuclear and missile facilities continue to run.
"If the United States responds to our active and pre-emptive efforts with trustworthy steps and corresponding behaviour, [relations] will move forward at an excellent and fast pace", Mr Kim said in his speech.
This year's speech drew intense attention, coming as U.S.
"To summarise North Korea's foreign policy strategy this year, it is to pressure the United States, to lead South Korea and to strengthen ties with China and Russian Federation", said Kim Heung Kyu, a professor of political science and diplomacy at Ajou University.
The North is demanding sanctions relief - it is subject to multiple measures over its banned nuclear weapons and ballistic missile program - and has condemned USA insistence on its nuclear disarmament as "gangster-like".
But Kim's speech on Tuesday called for a "complete end" to all joint exercises and slammed the sanctions campaign.
Since the first-ever summit between the USA and North Korea, little progress has been made as Pyongyang wants corresponding measures for the steps it has taken and Washington asks for more concrete steps before granting any quid pro quo.
Despite goodwill responses from Washington, such as a halt of some major military exercises with South Korea, U.S. officials have said North Korea's initial steps were not confirmed and could be easily reversed. The North is pushing in turn for measures from the U.S., like the easing of economic sanctions. He also pointed to a potential second meeting with Trump. Pyongyang over the past months has accused Washington of failing to take corresponding measures following the North's unilateral dismantlement of a nuclear testing ground and suspension of nuclear and long-range missile tests.
The Mount Kumgang tours were suspended after South Korean tourist Park Wang-ja was shot dead by a North Korean soldier in July 2008.
Although Kim's address - which is an annual tradition in North Korea - is aimed mainly at a domestic audience, global observers parse his words to get a sense of the secretive Pyongyang regime's intentions.