Officials have only a fortnight left to finalise thorny protocol details such as where in Singapore the talks will take place and how internationally sanctioned North Korean officials will travel there.
Kim Yong Chol, a four-star general who has been at the forefront of North Korea's diplomatic outreach, landed at Beijing Capital International Airport on Tuesday, according to television footage from the airport.
There had been speculation that Kim, who greeted Secretary of State Mike Pompeo in Pyongyang this month, would be traveling to the United States amid frenzied talks aimed at salvaging the summit, scheduled to be held in Singapore on June 12.
According to reports based on sources, Washington wants Pyongyang to ship its nuclear warheads, or possibly its intercontinental ballistic missiles, to the U.S. - most likely to a facility in Oak Ridge, Tennessee.
Yonhap said Kim Yong-chol's name was on the passenger list for a flight on Wednesday from Beijing to NY. Trump did not specify who Kim would be meeting with, or if he was heading to Washington D.C.in addition to NY.
It all started in February at the 2018 Winter Olympics in Pyeongchang, South Korea, when South Koreans and North Koreans walked under one united flag for the first time in history. Kim was accompanied by Choe Kang-il, a diplomat in charge of US affairs, who was also seen at the airport.
The former spy chief's current official position is vice-chairman of the Central Committee of the Worker's Party of Korea, but he rose to prominence as Pyongyang's chief military negotiator during inter-Korean talks between 2006 and 2008. Sung Kim is a former U.S. ambassador to South Korea and was a top negotiator with North Korea in past nuclear talks.
The introduction of Gen Kim to negotiations is significant, as it underlines North Korea's desire to ensure the talks go ahead.
Trump sent a letter last week to Kim Jong Un saying the summit scheduled for June 12 would not happen, blaming what he said was "tremendous anger and open hostility" shown in a statement by the North Korean leader.
Chung Sung-yoon, an analyst at the Korea Institute for National Unification, said Kim Yong Chol would be the most senior North Korean on U.S. soil since Vice Marshal Jo Myong Rok met then president Bill Clinton in 2000. And, on Sunday, the president said an American delegation was meeting with North Korean officials in preparation for the meeting. 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. Kim Jong Un agrees with me on this.
Kim is believed to be behind the sinking of a South Korean Navy ship known as the Cheonan in 2010 that ultimately killed 46 sailors.
The Koreas have agreed to put high-level discussions back on track with a meeting on Friday.
Trump is the first US president in recent times to open a constructive dialogue with North Korea.
North Korea has demanded the United States stop military exercises with South Korea, the North's Rodong Sinmun newspaper said.
Despite Kim's apparent eagerness for a summit with Trump, there are lingering doubts about whether he will fully relinquish his nuclear weapons, which he may see as his only guarantee of survival.
North Korea insists on guarantees that Kim's regime would remain in power if it abandoned its nuclear programme.
Perhaps more importantly in regards to any USA visit, he has also served as "the key interlocutor for Pompeo" in the top American diplomat's capacities as both Central Intelligence Agency chief and secretary of state.
The officials may discuss bridging the gap between the two sides on what a deal on the North's nuclear weapons would look like. North Korea has officially denied the incident.
Choe previously served as a deputy director of the Foreign Ministry's North American Affairs Bureau and was an aide and interpreter in the now defunct six-party talks to denuclearize North Korea.