Asked about the abrupt cancellation of the North-U.S. summit, Cho did not elaborate, saying he will look into what Trump said in the letter and figure out the overall situation.
But within 24 hours he reversed course, saying it could still go ahead after productive talks were held with North Korean officials.
Many outlets called it a "dramatic turn" in a series of diplomatic flip-flops as groundwork is laid for an unprecedented summit between North Korea and the U.S.
His remarks came nearly simultaneously with the announcement by Moon about his meeting with the North Korean leader. He also said that a date of June 12 in Singapore is still being considered for the meeting. "That hasn't changed", he said.
"The White House pre-advance team for Singapore will leave as scheduled in order to prepare should the summit take place", Sanders said.
While maintaining that Mr Kim is committed to denuclearisation, Mr Moon acknowledged Pyongyang and Washington may have differing expectations of what that means, and he urged both sides to hold working-level talks to resolve their differences.
It remains unclear whether Kim will ever agree to fully abandon his nuclear arsenal in return, despite Moon's insistence that Kim can be persuaded to abandon his nuclear facilities, materials and bombs in a verifiable and irreversible way in exchange for credible security and economic guarantees.
Moon said the Pyongyang regime reaffirmed its commitment to give up its nuclear weapons but had its own security concerns if it took that step. "Particularly because both Chairman Kim and President Trump both sincerely want a successful North Korea-U.S. summit, I stressed that the two sides should kill any misunderstanding through direct communication and let their deputies talk sufficiently to discuss the summit agenda", Moon told reporters.
Trump added: "We'll see what happens". Earlier, Yonhap, citing North Korean state media, reported that the leaders of two Koreas agreed to meet for a third time on June 1.
Specifically, Moon and Kim will hold "high-level talks" on Friday, the agency added.
"North Korea can still survive under sanctions, especially if China helps it", analyst Shin Beom-chul, a senior fellow at the Asan Institute for Policy Studies in Seoul told the Times.
Moon Jae-in with Kim Jong Un on Saturday.
Hours after news broke of the surprise meeting between the leaders of the two Koreas, President Trump made a short, simple comment on it.