Kim arrived Sunday at the St. Regis hotel, where his close aide has been based as he leads a North Korean advance team arranging security and logistics details.
Ever since Trump shocked allies, White House officials and, by some accounts, the North Koreans themselves when he accepted Kim's March invitation for a meeting, the two leaders have lurched toward an uncertain encounter that could affect millions.
Kim and President Trump arrived in Singapore on Sunday ahead of Tuesday's historic summit. The official was not authorized to comment publicly about on internal deliberations and requested anonymity.
But he has since lowered expectations, saying the talks would be more about starting a relationship with Kim for a negotiating process that would take more than one summit.
Later in the month, Trump chose to meet with Kim.
Trump has offered to reduce economic sanctions on North Korea in exchange for denuclearization. If North Korea intends on being an ally of the United States, it must not only give up its tools of destruction but also work with us to build a world of peace and stability.
South Korean President Moon Jae-in and North Korean leader Kim Jong-un agreed in a historic summit on April 27 to hold a reunion of separated families on the occasion of the August 15 Liberation Day.
"We are also planning a briefing by senior administration officials in the filing centre at the JW Marriott tentatively scheduled for 5pm local time", she said in the briefing note issued in Washington yesterday.
Kim Dae-jung, who fought North Korean communist guerrillas during the Korean War, was adamant that there must not be war again on the peninsula, and that the fate of the region should not be left in the hands of superpowers.
In return, Kim called him "mentally deranged" and a "dotard".More news: Food Twitter Roasts Trump and Kim Jong-un Over Summit Lunch
Lee is due to met Kim later on Sunday and Trump on Monday.
"It depends at least as much in what the USA does as what North Korea promises", he said.
Since becoming the leader in 2011, Kim previously took one known overseas trip by air - to Dalian in China in early May.
Sources told CNN that USA officials have established a contingency plan for a potential second day of discussions between Trump and Kim depending on the direction of their planned meeting on June 12.
In a meeting with former Secretary of State Madeleine Albright, Kim was asked 14 critical questions about the North's missile program, Sherman said.
An air of mystery continued to surround much of the Trump-Kim summit.
Whether Trump is truly winging it or he just wants everyone to think so after days of quiet preparations is unclear. He said he could invite Kim to the White House for further discussions. The test failed. Three months later, North Korea tested its first nuclear device near the village of Punggye-ri. He called for North Korea to follow a "Libya model" in negotiations.
This will be the first summit of its kind between a leader of North Korea and a sitting US president.
"I am on my way to Singapore where we have a chance to achieve a truly wonderful result for North Korea and the World".
The ensuing recognition as a "normal country" could then allow sanctions relief, and later worldwide aid and investment.
For the North, Kim Jong Un has already won a huge propaganda bonus by merely having the summit and sitting down as an equal with the USA president, an accomplishment his father and grandfather sought but could never realize.