US President Donald Trump and North Korean leader Kim Jong-un are poised to meet for an unprecedented summit on Tuesday aimed at defusing tensions on the Korean peninsula.
No sitting US president has ever met a North Korean leader.
Mr Trump has said the highly anticipated talks represent a “one-time shot” at peace.
The meeting marks a dramatic shift in relations between the pair, who last year traded insults and threats of war.
Washington hopes the summit will kick-start a process that eventually leads to the denuclearisation of North Korea, although what that actually means is likely to be contested.
Mr Trump left his hotel shortly after 08:00 (00:00 GMT), and is now making his way to the summit venue.
North Korea has said it is willing to commit to denuclearisation, but it is unclear how this will be achieved or what might be requested in return.
The summit will be held at a hotel on Sentosa, a popular tourist island a few hundred metres off the Singapore mainland, at 09:00 local time (01:00 GMT). Heavy security and armed police are standing guard at summit-related venues across the city state.
In his latest tweet, hours before the summit was due to begin, Mr Trump attacked his critics who have been arguing that the US president should not be meeting the North Korean leader.
Mr Trump earlier said meetings between the two sides’ officials were “going well and quickly”.
He continued: “But in the end, that doesn’t matter. We will all know soon whether or not a real deal, unlike those of the past, can happen!”
Mr Kim spent the evening before the meeting visiting some of Singapore’s tourist sites.
He smiled and waved to excited crowds and was accompanied by Singapore’s foreign minister, who tweeted a selfie standing next to him.
Tuesday’s front page of North Korea’s official newspaper also featured the extraordinary scenes on display in Singapore, for many North Koreans an unprecedented glimpse of their leader in a setting utterly at odds with their daily life.
The paper quotes how he saw the “current level of socioeconomic development of Singapore while looking at the ‘Sky Park’ on top of ‘Marina Bay Sands'”.
Analysts say that in the North Korean coverage Singaporean officials were essentially presented as tour guides to their “honoured guests”.
Why is this remarkable?
For decades, North Korea has been a pariah state, and now its latest hereditary leader is being treated as a world statesman.
Last year, it would have been a rare sight to see a North Korean flag flying anywhere in Asia.
Now, Mr Kim – who runs a totalitarian regime with extreme censorship and forced-labour camps – is meeting and greeting dignitaries.
“The circus-like atmosphere might be amusing if the stakes weren’t so high,” wrote US campaigning group Human Rights Watch.
What is the agenda?
Few details of the agenda have been released. They are set to greet at 0900 local time (0100 GMT) and then have a one-to-one meeting before a working lunch.
Mr Trump will leave the country that same evening to return to the US. Mr Kim is reported to be flying out even earlier, at 14:00 local time.
What are the talks about?
The talks will focus on North Korea’s controversial nuclear programme.
“They have to de-nuke. If they don’t denuclearise, that will not be acceptable,” Mr Trump said ahead of the meeting.
US Secretary of State Mike Pompeo said the US would only accept “complete, verifiable and irreversible denuclearisation” – but would offer “unique” security guarantees.
A formal end to the Korean war may also be discussed. The 1950-53 conflict ended with a truce, not a final peace treaty. Mr Trump says signing a peace agreement would probably be “the easy part”.
How did we get here?
A sit-down with the US president is something North Korea has long pushed for.
It is an outcome that seemed unimaginable less than a year ago – when Mr Trump and Mr Kim exchanged streams of fiery insults – and North Korea conducted several ballistic missile tests in defiance of the international community.
But earlier this year North Korea demonstrated a new openness to diplomacy and held direct talks with Seoul.
The rapid improvement in relations between the North and South Korea – technically still at war – culminated with a historic leaders’ summit in April.
During this warming of relations between the two Koreas, March saw Mr Trump stun the world by accepting an invitation to meet Mr Kim.
Still, the road to the Singapore talks has been far from smooth.
The lead-up to the summit has been marked by uncertainty and waves of frenetic diplomacy – at one point, Mr Trump even briefly called off the summit.
Talks of this kind typically take months to prepare. Critics fear that Mr Trump is poorly prepared for the negotiations – while others say Mr Trump’s quickfire approach has already produced results – including North Korea saying it is willing to consider denuclearising.
What do both sides want?
The US wants North Korea to get rid of its nuclear weapons in an irreversible manner that can be verified by the international community.
But analysts question why Mr Kim would give up his nuclear weapons after pushing so hard to get them. They also say by winning the prestige of a meeting with the world’s most powerful leader, Mr Kim has already gained a victory.
The North Korean leader has also said he now wants to focus on building the country’s economy – and wants sanctions relief and international investment.
Still, the US is not expecting a final deal in Singapore. President Trump has described it as a “get-to-know-you situation” .
The US president has also said that if he thinks things are going badly, he will walk out of the meeting, but if things go well, Mr Kim could receive an invitation to the White House.