Donald Trump on Kim Jong-Un: We will meet many times

Donald Trump has formed a "special bond" with North Korea's leader Kim Jong Un, he said Tuesday at the end of a historic meeting during which the two former foes pledged to meet again.

The pair signed what Trump called a "pretty comprehensive" and "very important" document, which spoke of "new US-DPRK relations" and committed Washington to "security guarantees".

However, asked about denuclearisation - the crux of the summit, Trump said "we're starting that process", adding that it would begin "very, very quickly." For his part, Kim said the two Cold War foes had vowed to "leave the past behind", pledging "the world will see a major change." The extraordinary summit comes after the two nuclear-armed foes appeared on the verge of conflict late last year as they slung personal insults and Kim conducted nuclear and missile tests.

It was the first-ever meeting between sitting leaders of the two countries and was closely watched around the world. "We'll meet again," Trump said after a signing ceremony, standing with Kim on the verandah where they first met. "We will meet many times."

Trump said he "absolutely" would be willing to invite Kim - whose regime has been criticised for widespread human rights abuses - to the White House. Earlier, the pair shared warm words and a historic handshake as they sought to confront a nuclear stand-off and enmity stretching back decades. The two men shook hands for several seconds beneath the walls of an upscale hotel in Singapore, Trump reaching out to touch the North Korean leader on his right shoulder.

In Seoul, South Korean President Moon Jae-in watched live on television, telling his ministers, he "could hardly sleep last night". However, some analysts have warned the summit could produce more style than substance.