Mr. Trump, in comments during his May 22 White House meeting with South Korean President Moon Jae-in, referred specifically to North Korea's "change in attitude" after North Korean leader Kim Jong-un's recent second meeting with Mr. Xi in just over a month.
"We have put a great team together for our talks with North Korea", Mr Trump said in a tweet today.
Trump views a summit as a legacy-defining opportunity to make the nuclear deal that has evaded others, but he pledged to walk away from the meeting if he believed the North wasn't serious about discussing dismantling its nuclear program.
Kim Yong Chol, a vice chairman of the ruling Workers' Party who was seen in the Beijing airport on Tuesday by The Associated Press, has been deeply involved in the diplomacy that followed Kim Jong Un's sudden outreach to Washington and Seoul earlier this year.
"Solid response to my letter, thank you!"
Secretary Pompeo is also heading to NY this week to meet a top North Korean official, Kim Yong Chol.
Anchor: Working-level discussions between North Korea and the United States are under way in Korea and Singapore in advance of a possible summit.
North Korea claimed to be surprised and "full of regret" at President Donald Trump's decision to cancel the planned meeting with North Korean leader Kim Jong Un in Singapore.
Kim Yong Chol is to meet with U.S. Secretary of State Mike Pompeo. Since then, North Korea has rejected United States demands for it to unilaterally abandon its nuclear weapons programme.
A team led by Sung Kim, a former American negotiator with North Korea who now serves as ambassador to the Philippines, is holding another round of talks Tuesday on the northern side of the demilitarized zone that separates the two Koreas. It is reported by Japanese TV channel TBS.
On Sunday, Moon also said Kim reaffirmed his commitment to "complete" denuclearization of the Korean Peninsula in talks the two leaders held the day before at the demilitarized zone.
Sung Kim, the former US ambassador to South Korea and current ambassador to the Philippines, led that American delegation, an American official told Reuters. "The fact that Kim Yong-chol is visiting the USA - that in itself means that coordination between the two is nearly over, . with only a few factors left to be resolved".
Kim Chang-son (L), North Korean leader Kim Jong-un's de facto chief of staff, prepares to get into a auto as he leaves a hotel in Singapore on May 29, 2018.
In an odd twist, a list of potential concessions by North Korea in the Central Intelligence Agency analysis included the possibility that Kim Jong Un may consider offering to open a Western hamburger franchise in Pyongyang as a show of goodwill, according to three national security officials. "We will to do everything we could for peace and stability of the Korean peninsula and humankind, and we, broad-minded and open all the time, have the willingness to offer the USA side time and opportunity", Kim Kye Gwam wrote.
There could be division under Kim within North Korea's hierarchy about the diplomatic approach to the Americans, according to Bennett.
Gen. Kim has also been blamed by South Korea for the 2010 sinking of a South Korean naval vessel, the Cheonan, which killed 46 seaman. Secretary of State Madeleine Albright made a historic reciprocal visit to Pyongyang later in 2000 in a bid to arrange a North Korea visit by Clinton. Secretary of State Mike Pompeo is also headed to NY.
If the June 12 date stands, officials have only two weeks to finalize details such as where in Singapore the talks will take place and how internationally sanctioned North Korean officials will travel there.
North Korea denied any involvement in both attacks.
The United States has demanded the "complete, verifiable, and irreversible" dismantlement of North Korea's nuclear weapons programme.