The White House has said its policy of "maximum pressure and engagement" was created to use sanctions to push the regime of Kim Jong-un to the negotiating table to talk about the future of his nuclear weapons programme. However, the North has yet to corroborate the South Korean statement.
"We remain determined to achieve a de-nuclearisation of the Korean Peninsula", Trump told reporters at a joint White House news conference with the Swedish Prime Minister.
Tensions over North Korea's nuclear and missile programmes rose to the highest level in years in 2017.
Cha's nomination was withdrawn because he criticised a plan to carry out a "bloody nose" punitive strike against North Korean weapons sites. But South Korean envoys who met with Kim earlier this week say they informed the North's leader that it wasn't feasible to postpone the military drills. "But we'll see what happens".
China's Foreign Ministry spokes-man Geng Shuang said yesterday that Beijing was "very pleased to see positive results" from interactions between the two Koreas, and China was willing work with other nations to promote denuclearisation. "The proper way is the way that everybody knows and everybody wants". "We're prepared to go whichever path is necessarily".
The official said Chung had already spoken to McMaster on the phone shortly after completing this week's visit to North Korea.
The diplomatic source told the Post that Chung will deliver "conditions from the North Korean side to start some bilateral dialogue with the United States".
South Korean President Moon Jae In has said that efforts to establish peace in the region had reached a "very critical juncture", but his country would not settle for anything less than the denuclearisation of the North. "I think you are going to see a drop-off in worldwide support for pressure for pressure's sake".
South Korea's opposition parties were sceptical of Tuesday's announcement.
"North Korea has clearly expressed its intention for denuclearization on the Korean peninsula, and if there is no military threat and North Korea's regime security is promised, they have clarified that there is no reason to hold nuclear weapons", South Korean President Moon Jae-in's office said.
Trump's sometimes brash rhetoric and his love for picking a fight via Twitter, while a point of contention at times even among his own staff, also appears to have had an effect at bringing North Korea to the negotiating table.
A South Korean delegation returned home on Tuesday from a first-ever meeting with North Korean leader Kim Jong-un, to announce the agreement on a North-South summit next month, the first since 2007.
He urged China to halt its "forced repatriations" of North Koreans crossing the border, whom Beijing regards as economic migrants and not as people fleeing persecution, saying they faced the risk of torture on return.
Chung and Suh will also meet senior USA officials like White House National security advisor H.R. McMaster and Central Intelligence Agency director Mike Pompeo.
Kimura also said it is possible that prior to Kim's meeting with the South Korean delegation, Washington and Seoul had secretly discussed its details while purposely keeping Japan out of the loop.
Talks began on Wednesday on cost-sharing for the U.S. military presence on the Korean peninsula.