Trump struck an optimistic tone about his talks with Kim.
"Kim Ju-song interpreted for Kim Yong-chol when he met with Central Intelligence Agency officials", a source said.
As reports emerged that the South Korean government was surprised by the announcement, questions were raised about whether Mattis and other US policymakers had also been caught off guard. The missiles flew back into to their launchers, and a science-fiction like version North Korea took its place - one of crane-dotted skylines, crowded highways, computerised factories and drones, all presided over by a waving, grinning Kim.
"The world will see a major change", he continued through a translator.
The Trump administration is also dealing with a North Korea that has a much more sophisticated nuclear weapons program, with more powerful warheads and more accurate intercontinental ballistic missiles.
In the end, he simply hitched a ride from his pal President Xi Jinping on an Air China Boeing 747 - a surprising move given North Korea's insistence on "juche" or self-reliance.
Hours earlier as he sat alongside Kim at the signing ceremony, Trump said the two leaders "have developed a special bond" and that after their several hours of talks Tuesday and the signing of the agreement he thinks the US relationship with North Korea "will be very different than in the past".
And as they emerged from the meal for a brief stroll together, Trump appeared to delight in showing his North Korean counterpart the interior of "The Beast", the famed US presidential limousine known for its high-tech fortifications.
Trump declared he and Kim had developed "a very special bond".
"I think he loved it", Trump said during his post-meeting news conference.
The meeting was the first between a sitting USA president and a North Korean leader.
"Of those alive today, only a small number will leave a lasting impact", the narrator said near the beginning, as alternating shots of Trump, Kim and North Korean pageantry flashed on the screen.
A confident leader strode into the Singapore summit and won.
The agreement's language on North Korea's nuclear program was similar to what the leaders of North and South Korea came up with at their own summit in April.
The president was more talkative when discussing how Kim had reacted to the video, which Trump had presumably played for him during a brief, private meeting hours earlier.
"The good news is that longtime adversaries have shown that they can talk and now the White House has a channel with the top leader in Pyongyang", Mr. Cronin told The Washington Times.
This language certainly covers the underlying issues encompassed in North Korea's definition of hostile United States policy, but the lack of detail and the mirroring of past commitments is concerning.
Ahead of the meeting Trump had predicted the two men might strike a nuclear deal or forge a formal end to the Korean War in the course of a single meeting or over several days.
As of Tuesday morning, United States Forces Korea, who conducts the exercises, said in a statement they had received "no updated guidance on execution or cessation of training exercises".