Donald Trump said he didn't have time to include in his agreement with Kim Jong-un guarantees that North Korea's disarmament would be "verifiable and irreversible".

He also didn't have time to discuss the issue of a peace treaty with the South. "I'm here one day," he retorted when pressed by journalists about why the letter the two leaders had signed seemed to lack detail.

But he did have time to show a four-minute film to Kim and his entourage on an iPad.

With a Hollywood trailer-style voiceover, the video describes: "Two men, two leaders, one destiny."

And against the backdrop of a basketballer dunking into a hook, the soundtrack presents: "A story about a special moment in time when a man is presented with one chance that may never be repeated What will he choose? to show vision and leadership... or not."

The rest of the clip is dedicated to showing a potential bright future for North Korea, featuring speedboats, drones, skyscrapers and dodgems and pineapples.

After their morning meeting, Kim had said that he felt many people felt that the occasion was something out of a science fiction film.

"I think he loved it," Trump later told the world's gathered press, who had sat through a showing in Korean and English before his appearance.

Asked whether he was worried that the video, which depicts Trump and Kim deciding the future of the world, could serve as propaganda, the US president stated he was "not concerned at all."