No details were given on any possible progress in preliminary talks between aides at the talks. U.S. Secretary of State Mike Pompeo, who is also in Singapore, said in a tweet that Washington was "committed to the complete, verifiable, irreversible denuclearisation of the Korean peninsula".
Critics of the summit leapt at the leaders' handshake and the moonlight stroll Kim took Monday night along the glittering Singapore waterfront, saying it was further evidence that Trump was helping legitimize Kim on the world stage as an equal of the US president.
So the summit was almost derailed by talk from Trump's hawkish National Security Advisor John Bolton of a "Libya model" of disarmament.
"Great to be in Singapore, excitement in the air!"
Menendez spoke Sunday on ABC's "This Week" as President Donald Trump arrived in Singapore ahead of Tuesday's talks with Kim.
The first word Kim is in Singapore for Tuesday's summit came early Monday morning.
Chairman Kim yesterday held a meeting with Prime Minister Lee.
During negotiations, the Americans were impressed by Kim's mastery of missile technicalities.More news: Cohen likely to cooperate with federal prosecutors
It will be the first meeting between a sitting USA president and a top DPRK leader.
In recent days, Trump had suggested the meeting could last days, potentially even resulting in a nuclear deal.
Trump responded to such commentary on Twitter, saying: "The fact that I am having a meeting is a major loss for the USA, say the haters & losers".
Kim will likely spend the remaining days at the hotel focusing on last-minute preparations with his top officials for Tuesday's summit. But many, if not all analysts, say that this is highly unlikely, given how hard it has been for Kim to build his program and that the weapons are seen as the major guarantee to his unchecked power. A Trump administration official, speaking on condition of anonymity, said the USA side was entering the talks with a sense of optimism and an equal dose of scepticism given North Korea's long history of developing nuclear weapons.
White House Press Secretary Sarah Sanders said that the President, Secretary of State, White House Chief of Staff, and National Security Adviser have arrived in Singapore for the June 12 summit.
White House press secretary Sarah Huckabee Sanders said Sung Kim, the US ambassador to the Philippines who has taken the lead on policy negotiations with the North, will hold a "working group" with a North Korean delegation to discuss final preparations for the meeting. The leaders themselves had little to say.
Trump, who is offering to reduce economic sanctions on North Korea in exchange for denuclearization, also seemed to warn Kim that the summit is a "one-time opportunity" that should not be wasted.
But after a flurry of diplomatic overtures eased tension in recent months, the two leaders are now headed for a history-making handshake that USA officials hope could eventually lead to the dismantling of a North Korean nuclear programme that threatens the United States.More news: FG declares Friday, Monday public holidays
"I delivered the speech on behalf of him, which was virtually his posthumous work", said Chung Dong-young, Lee's predecessor as unification minister.
The Trump-Kim meeting will cost about S$20 million to host, Singapore's Prime Minister Lee Hsien Loong told local media on June 10, a large chunk of that expected to be on security on the highest profile event the city-state has ever hosted.
A USA official says Monday that the leaders will meet for up to two hours before an expanded bilateral meeting with their respective advisers.
Again accusing the longtime USA ally of unfair trade practices, Trump added: "Then Justin acts hurt when called out!"
It is an extraordinary turnaround from the rhetoric of previous year, when Mr Trump threatened the North with "fire and fury" and Mr Kim dubbed him a "mentally deranged U.S. dotard".
Even if Kim offers only "a fine-sounding rhetorical commitment, and maybe a few missiles surrendered or some site closures", he said, Trump will "market this thing as something extraordinary for his voters back home". The meetings also served as an ice breaker of sorts as the teams worked to get better acquainted after decades of minimal U.S. The president hopes to win a legacy-making deal with the North to give up their nuclear weapons, though he has recently sought to manage expectations, saying that it may take more than one meeting. The former businessman said he has spend a lifetime preparing for negotiations of this type, and predicted he would know in an instant if Kim is serious about the topic of denuclearization. "You would start at least a dialogue, because, you know, as a deal person, I have done very well with deals".
Iran, meanwhile, reminded Kim that Trump should not be trusted because he could nullify any nuclear deal with North Korea, just as he pulled out of the landmark 2015 nuclear deal with Tehran.More news: Lesbian couple kicked out of Uber by 'homophobic' driver