Trump and Kim planned to meet one-on-one for most of an hour- joined only by translators. But he also made clear Kim has a "one-time shot".
Lobster bisque, beef tenderloin and ice cream were on the lunch menu, and there was also an early birthday cake for Trump, who turns 72 on Thursday. Those include terminating America's military presence in South Korea as well as ending the US regional nuclear umbrella, a security arrangement in which Washington promises in-kind retaliation on behalf of close allies if they are attacked with nuclear weapons.
Seoul's Unification Ministry said Monday the surveys conducted through home visits, phone calls and letters will continue through August 10.
Pyongyang has said it is willing to deal away its entire nuclear arsenal if the United States provides it with reliable security assurances and other benefits. He most recently travelled there a year ago as a private citizen.
The Koreas plan to hold military talks Thursday to reduce tension across their heavily armed border.
Trump's early exit will be his second from a summit in just a few days.
A USA official says Monday that the leaders will meet for up to two hours before an expanded bilateral meeting with their respective advisers.
Tuesday's summit will be the first between a North Korean leader and a sitting American president. The only sane reaction is to hope that they do both get along.
The area includes the summit venue, Capella Hotel on Sentosa Island and the places around Shangri-La Hotel and the St. Regis Hotel where Trump and Kim are expected to stay, respectively.
Trump was quiet after touching down in Singapore on Sunday night but was back online first thing Monday morning, engaging Trudeau again in a war of words.
Mr Kim arrived in Singapore on a loaned Chinese jet
A report by the Korea Central News Agency said the summit would have "wide-ranging and profound talks" and noted that it is being held "under the great attention and expectation of the whole world".
Another question is whether Trump will take up the issue of human rights - with North Korea accused of a host of state-sanctioned rights abuse including extrajudicial killing, torture and kidnapping.
During the flight, the president spent time meeting with his staff, reading materials, and preparing for his meetings in Singapore.
But it is Mr Kim's pursuit of nuclear weapons that gives his meeting with Mr Trump such high stakes.
While advisers say Trump has been reviewing briefing materials, the president insists his gut instincts will matter most when he gets in the room with Kim. The deal collapsed in 2002, when USA officials accused North Korea of covertly running a nuclear program using enriched uranium.
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. The meeting is expected to begin around 8:45 p.m. (8:45 a.m.in Singapore).
In the summer of 1976, two American soldiers were hacked to death by ax-wielding North Korean soldiers during a fight over USA efforts to trim a poplar tree at Demilitarized Zone that bisects the Koreas.
The 2 leaders shook hands.
Kim smiled broadly in the meeting Sunday evening.
Californians to vote on splitting state three ways
The northern part of the state (including San Francisco and current state capitol Sacramento ) would become Northern California . The third state, California , would cover six counties in the coastal area stretching between Monterey and Los Angeles.