He said: "They're putting down a marker, saying which way things are headed if nothing changes".
I want to make it clear that the gangster-like stand of the United States will eventually put the situation in danger.
At a news conference after the second summit, Mr Trump said no plans had been made for a third summit, but he expressed optimism about a "good outcome" in the future.
Moon Chung-in, South Korea's special presidential adviser for foreign affairs and national security, said if Pyongyang tries to use the reported missile activities as leverage in stalled nuclear talks, it would constitute a "bad move" that could be catastrophic.
North Korea is considering breaking off negotiations with the US and resuming nuclear and missile tests, following last month's summit in Vietnam that ended early and without an agreement, a government official said.
"We are not going to do denuclearization incrementally", Biegun said. Talks between Mr Trump and Kim - the second time the two leaders have met - collapsed as a result the latter's demands over global sanctions imposed in response to nuclear weapons programme, which it pursued for years in defiance of UN Security Council resolutions.
Two weeks after U.S. President Donald Trump and North Korean leader Kim Jong Un cut short their second summit with no agreement or clear path forward, a top North Korean official said on Friday the "gangster-like" behavior of Trump's hawkish top officials helped derail the denuclearization negotiations.
Russian Federation and China, which border North Korea, have the relatively closest diplomatic relations with the extremely insular North Korean state. "So that's Chairman Kim's word".
Mr Pompeo said Kim Jong-un had promised US President Donald Trump in Vietnam that testing would not resume.
Choe blasted Washington chiefs, claiming they threw away a "golden" opportunity at its recent summit and added Kim might rethink a moratorium on missile launches and nuclear tests.
"I'm not sure why the USA came out with this different description", Choe said. "We have every expectation that he will live up to that commitment".
In Washington this week, the USA special representative for North Korea, Stephen Biegun, said the United States expected to be able to continue its close engagement, though he offered no specifics on when new talks might be held.
Trump has pointed to North Korea's freeze in nuclear and missile testing since 2017 as a positive outcome from almost a year of diplomatic engagement with North Korea.
What did Pompeo and Bolton say?
United States national security adviser John Bolton, who has argued for a tough approach to the North, said last week that Trump was open to more talks but warned of tougher sanctions if Kim did not denuclearise.
Trump told reporters at the time that the US would be unable to accept North Korea's request for total sanctions relief as a precondition for disarmament.
The North´s warning came amid concerns over its satellite rocket launch site, where some rebuilding activity has been observed in recent weeks, triggering global alarm that Pyongyang might be preparing a long-range missile or space launch.