On Saturday, Kono was to meet with South Korean Foreign Minister Kang Kyung-wha in Washington to exchange views on the summit planned between Moon and Kim.
While pledging to keep maximum pressure on Pyongyang, Trump and Moon "expressed cautious optimism over recent developments and emphasized that a brighter future is available for North Korea, if it chooses the correct path", it said.
Trump has chosen CIA Director Mike Pompeo to replace Tillerson, but Pompeo is not able to contact the foreign ministers of the two Koreas until his nomination is approved by the Senate.
In 2017 North Korea held a number of missile tests to check its nuclear capability. "I think he'd be a happy man if we abrogated our alliance with South Korea". -South Korean trade issues, with Trump asking South Korea to "show flexibility" in negotiations and seeming to stand by his assessment of current trade agreements as "unfair" to the United States.
The planning is at "a very early stage", the official said.
Mr Suh was one of two South Korean envoys who visited the White House last week to brief Mr Trump on their meeting with Kim Jong Un in Pyongyang a few days earlier. "It is up the parties to decide how to move forward", Wallstrom told Swedish media in parliament on Friday.
Danny Boyle working on "Bond 25"
So, when that's in the can, he says, "Then Bond would be right at the end of the year". Danny Boyle has said that he is working on a script for the 25th James Bond movie.
"What I hope comes out of the summit is that President Trump and Kim Jong Un paint a broad brush of the framework of where we need to go, agree on some principles and agree to kick off a process", he told CNN.
Still, some diplomats said they were not concerned about the CIA's role, as long as the meeting did not get derailed.
Choe accompanied the high-level North Korean delegation to the closing ceremony of last month's PyeongChang Winter Olympic Games.
The time and location of the Trump-Kim summit have yet to be determined, although neutral countries such as Sweden and Switzerland have been floated as possible hosts.
There had been speculation that Pyongyang might do so Friday, when Ri Yong Ho met Swedish Prime Minister Stefan Lofven and Foreign Minister Margot Wallstrom, but afterwards Swedish officials said the talks would be extended into yesterday.
The isolated state has always maintained it will continue to develop its nuclear weapons as a deterrent against U.S. aggression but, according to South Korea, it later said it was open to abandoning the programme if the security of its regime was guaranteed.