South Korea's Foreign Ministry has described Donald Trump's decision to call off a trip by his Secretary of State Mike Pompeo to North Korea as "unfortunate", but says it is most important for the allies to pursue "substantial progress" on denuclearisation.
The statement by the Foreign Ministry in Seoul on Saturday came hours after the US president ordered Pompeo to delay his trip because of what he sees as a lack of progress on nuclear disarmament talks with North Korea.
The ministry said South Korean foreign minister Kang Kyung-hwa spoke with Pompeo over the phone and they pledged joint efforts to keep the momentum of dialogue alive.
Trump has also accused China for its supposed lack of support in US-led diplomatic efforts to rid North Korea of nuclear weapons and missiles.
But China hit back, with its Foreign Ministry saying on its website the US statement "violates basic facts and is irresponsible."
It also said it is "seriously concerned about it" and has made "solemn representations to the US side".
Trump's statement on Friday that the North Korea trip wouldn't go ahead came just a day after Pompeo said he would make his second visit to North Korea next week and would take his new special envoy Stephen Biegun with him.
Trump was still open to another meeting with Kim, in hopes of advancing the process but was not pleased with the latest signals from North Korea, a White House official said.