A North Korean delegation in New York for talks will travel to Washington today to deliver a letter from North Korean leader Kim Jong Un, President Donald Trump has said.
In brief remarks to reporters at an air base outside Washington as the American and North Korean teams began a morning of talks in New York, Mr Trump said their dinner meeting on Wednesday had gone "very well".
But it did not mean everything would get done in one meeting on June 12, he added. "Maybe we have to have a second or a third. And maybe we will have none. But, it is in good hands," he said.
Steak, corn, cheese and nuclear weapons were on the dinner menu in New York, where Secretary of State Mike Pompeo sat down with Mr Kim's right-hand man, General Kim Yong Chol.
The former spy chief arrived in New York on an Air China flight from Beijing, becoming the most senior North Korean official to visit the US in almost two decades.
It was his third meeting with Mr Pompeo, who visited Pyongyang twice in recent weeks.
Photos showed Mr Pompeo pointing out Manhattan landmarks from the US diplomatic residence on a high floor of The Corinthian condominium, a few blocks from the United Nations.
At stake is what each side is prepared to commit at a planned Trump-Kim summit in Singapore.
Joining Mr Pompeo for the morning's talks were Mr Andrew Kim, head of the Korean desk at the Central Intelligence Agency, Mr Mark Lambert, a deputy assistant secretary of state and special representative for North Korea, and a translator.
"The potential summit... presents (North Korea) with a great opportunity to achieve security and economic prosperity," Mr Pompeo tweeted ahead of the meeting. "The people of North Korea can have a brighter future and the world can be more peaceful."
Earlier, a senior State Department official told journalists in New York: "Between now and if we are going to have a summit, they're going to have to make clear what they are willing to do.
"In all of our... messaging we have been clear that what we are looking for is… complete, verifiable, irreversible denuclearisation."
For the summit to be successful, "the North Koreans have to do things that they have not done before", he said.
"We are willing to work with them to provide them the security guarantees they feel they need, and in fact, we are willing to go beyond that to help them have greater economic prosperity," he said. "But they have to denuclearise."
Meanwhile, American and North Korean officials continued talks at the truce village of Panmunjom on the North-South border on the Korean peninsula.
The US side is led by its Ambassador to Manila, Mr Sung Kim, a veteran of past negotiations with North Korea, and the North Korean side by its Vice-Foreign Minister, Ms Choe Son Hui. Discussions centre on the content of the June 12 summit.
And on a separate track in Singapore, a delegation from the North led by Mr Kim Chang Son, a senior official at the State Affairs Commission, has been meeting an American team led by White House Deputy Chief of Staff for Operations Joe Hagin to discuss logistics and security for the summit.
"The advance team, led by Deputy Chief of Staff Joe Hagin, met the North Korean team in Singapore earlier today, and again expect to do so tomorrow," White House Press Secretary Sarah Sanders told journalists in Washington.
"We want to thank our strategic partner in Singapore, who has been incredibly generous in agreeing to host the summit," she added. "And the President is very appreciative of Prime Minister Lee (Hsien Loong) for all of their efforts."
In Seoul, the Korea Times said in an editorial: "The fate of the Singapore summit will depend on how the two sides compromise and accommodate each other's demands."
It cautioned that "there are still many thorny issues standing in the way of the Kim-Trump meeting".