Donald Trump and Kim Jong Un have concluded an extraordinary nuclear summit with the US president pledging unspecified “security guarantees” to the North and Mr Kim recommitting to the “complete denuclearisation of the Korean peninsula”.

Meeting with staged ceremony on a Singapore island, the pair came together for a summit that seemed unthinkable months ago, clasping hands in front of a row of alternating US and North Korean flags, holding a one-on-one meeting, additional talks with advisers and a working lunch.

Both leaders expressed optimism throughout roughly five hours of talks and, speaking at a news conference after the meeting, Mr Trump thanked Mr Kim for “taking the first bold step toward a bright new future for his people”.

The president said “real change is indeed possible” and he is prepared “to start a new history” and “write a new chapter” between the two nations, adding: “The past does not have to define the future.”

Mr Trump added during a free-flowing news conference that Mr Kim has “an opportunity like no other” to bring his country back into the community of nations if he agrees to give up his nuclear programme.

The president announced he will freeze US military “war games” with ally South Korea while negotiations between the two countries continue. He cast the decision as a cost-saving measure, but Pyongyang has long objected to the drills as a security threat.

Donald Trump answers questions about the summitDonald Trump answers questions about the summit (Susan Walsh/AP)

Mr Trump acknowledged that the timetable for denuclearisation is long, but said: “Once you start the process it means it’s pretty much over.”

The president acknowledged that US intelligence on the North Korean nuclear stockpile is limited, “probably less there than any other country”, but added: “We have enough intelligence to know that what they have is very substantial.”

SINGAPORE Summit(PA Graphics)

Mr Trump sidestepped his public praise for an autocrat whose people have been oppressed for decades. He added that Otto Warmbier, an American once detained in North Korea, “did not die in vain” because his death brought about the nuclear talks.

Mr Trump said Mr Kim accepted his invitation to visit the White House at the “appropriate” time.

Light on specifics, the document signed by the leaders largely amounted to an agreement to continue discussions as it echoed previous public statements and past commitments.

It did not include an agreement to take steps towards ending the technical state of warfare between the US and North Korea.

Kim Jong Un listens to Mr TrumpKim Jong Un listens to Mr Trump (Evan Vucci/AP)

The pair promised in the document to “build a lasting and stable peace regime” on the Korean peninsula and to repatriate the remains of prisoners of war and those missing in action during the Korean War.

Language on North Korea’s bombs was similar to what the leaders of North and South Korea came up with at their own summit in April.

At the time, the Koreans faced criticism for essentially kicking the issue of North Korea’s nuclear arsenal down the road to the Singapore summit.

Mr Trump and Mr Kim even directly referenced the so-called Panmunjom Declaration, which contained a weak commitment to denuclearisation and no specifics on how to achieve it.