BEIJING: A top aide to the North Korean leader, Kim Jong-un, was on his way to the US on Tuesday, Donald Trump said in a tweet.
Another key aide to Kim arrived in Singapore on Monday night, a Japanese broadcaster said, adding weight to indications a planned summit with Trump will go ahead.
Kim Chang-son, Kim's de facto chief of staff, flew to Singapore via Beijing, the report by public broadcaster NHK said. South Korea's Yohnap news agency reported that Kim Yong-chol, a former North Korean spy chief and senior official, was headed to the US after stopping over in Beijing.
Trump appeared to confirm that in a tweet on Tuesday morning, sent in the middle of a sequence of complaints about the Russia investigation.
"We have put a great team together for our talks with North Korea," the US president wrote. "Meetings are currently taking place concerning Summit, and more. Kim Young [sic] Chol, the Vice Chairman of North Korea, heading now to New York. Solid response to my letter, thank you!"
Kim Yong-Chol is vice-chairman of the Workers' Party's Central Committee. Trump's reference to a letter was to his cancellation of the summit last Thursday.
A team of US officials including Joe Hagin, the White House deputy chief of staff for operations, left the Yokota airbase in Japan for Singapore on Monday, NHK said. The White House said a "pre-advance" team was travelling to meet North Koreans.
It said Trump and the Japanese prime minister, Shinzo Abe, talked on the phone on Monday and confirmed they would meet before the "expected" US-North Korea summit. Trump and Abe "affirmed the shared imperative of achieving the complete and permanent dismantlement of North Korea's nuclear, chemical, and biological weapons and ballistic missile programmes," the White House said in a statement.
The historic summit was initially scheduled for 12 June but Trump called it off last week. A day later, he said he had reconsidered and officials from both countries met to work out details.
When Kim Chang-son was asked by a reporter at Beijing airport if he was flying to Singapore for talks with the US, he said he was "going there to play", according to footage from Nippon Television Network.
On Saturday, Kim Jong-un and South Korean president Moon Jae-in at the border village of Panmunjom, during which they agreed the North Korea-US summit must be held a surprise meeting South Korean officials have said Moon may travel to Singapore during the meeting, but that his attendance is dependent on preliminary meetings between the US and North Korea.
On Sunday, the state department said US and North Korean officials had met at Panmunjom. Sung Kim, a former US ambassador to South Korea and current ambassador to the Philippines, led the American delegation, a US official told
Reuters.