North Korean leader Kim Jong Un attends a wreath laying ceremony at the Ho Chi Minh Mausoleum in Hanoi, Vietnam March 2, 2019. Credit: Jorge Silva | AP

TOKYO — North Korea is considering suspending denuclearization talks with the United States unless Washington changes its stance after the breakdown of a summit meeting in Hanoi between President Donald Trump and North Korean leader Kim Jong Un, a senior official said Friday.

Kim Jong Un is set to make an official announcement soon on whether to continue diplomatic talks and maintain the country’s moratorium on missile launches and nuclear tests, Vice Foreign Minister Choe Son Hui told foreign diplomats and journalists in Pyongyang, the Associated Press reported.

The threat to suspend talks comes after evidence surfaced that North Korea has rebuilt a satellite rocket launchpad and amid speculation it might be preparing a rocket launch, a move that would seen as very provocative in Washington.

Choe said North Korea was deeply disappointed by the breakdown of the talks in Hanoi and said the United States had missed a golden opportunity there, though she still described the relations between Trump and Kim as “mysteriously wonderful.”

She said Pyongyang now has no intention of compromising or continuing talks unless the United States changes its “political calculation,” and takes measures that are commensurate with the steps North Korea has already taken, such as the 15-month moratorium on launches and tests, AP reported.

“On our way back to the homeland, our chairman of the state affairs commission said. ‘For what reason do we have to make this train trip again?’” she said, referring to Kim.

“I want to make it clear that the gangster-like stand of the U.S. will eventually put the situation in danger,” she added. “We have neither the intention to compromise with the U.S. in any form nor much less the desire or plan to conduct this kind of negotiation.”

At the summit, Kim offered a partial shutdown of the Yongbyon Nuclear Research Center, where a large part of North Korea’s fissile material is produced, in return for lifting almost all the meaningful economic sanctions on his country, U.S. officials say.

Trump rejected that deal on the grounds that it would allow Pyongyang to continue producing weapons of mass destruction, effectively financed by the lifting of sanctions. Globally, there was widespread agreement that North Korea was offering too little and demanding too much.

But Trump’s counter-offer was also widely seen as unrealistic. He tried to convince Kim to “go big,” and surrender his entire arsenal of nuclear, chemical and biological weapons in return for “a bright future” economically.

Choe, who attended the Hanoi summit, said Kim was puzzled by what she called the “eccentric” negotiation position of the United States, but she said the North Korean leader still had a good relationship with Trump.

“Personal relations between the two supreme leaders are still good and the chemistry is mysteriously wonderful,” she said,while accusing Secretary of State Mike Pompeo and national security adviser John Bolton of creating an atmosphere of “hostility and mistrust.”

She said even though the North Korean people, military and munitions industry officials had sent Kim thousands of petitions to never give up the nuclear program, he went to Hanoi to build trust and carry out mutually agreed commitments “step by step,” AP reported.

“What is clear is that the U.S. has thrown away a golden opportunity this time,” Choe said. “This time we understood very clearly that the United States has a very different calculation to ours.”

She said it was entirely up to Kim whether to continue the launch and test moratorium, and said she expects he will “clarify his position” within a short period of time, AP reported.

Satellite images released last week showed North Korea has completed reconstruction of a rocket launchpad and rocket engine testing station at the Sohae Satellite Launching Station, with work beginning even before the Feb. 27-28 Hanoi summit.

Activity was also seen at a site in Sanumdong, just outside Pyongyang, that is North Korea’s primary developer of ballistic missiles and space launch vehicles, leading some experts to conclude that the launch of a space rocket was being planned — although that doesn’t mean it will go ahead.

Trump said last week he was “a little disappointed” at reports of the rebuilding work at Sohae, but added that time will tell if diplomacy will be successful.

Many experts see signs of a hardening of the U.S. stance post-Hanoi, with Bolton taking a leading role in the media ruling out any sanctions relief until North Korea fully denuclearizes and even threatening to ramp up sanctions.

U.S. envoy Stephen Biegun has also ruled out doing denuclearization “incrementally,” although he insisted on Monday that diplomacy was “still very much alive.”

John Delury, an expert on East Asia at Seoul’s Yonsei University, said Choe’s comments could be seen as a response to Bolton’s threat to ramp up sanctions, and didn’t mean the door to dialogue was closed.

“This is each side reminding each other what’s at stake,” he said.

Delury took heart from the fact that there was no name-calling or insults, while noting that Choe also took pains to praise Kim’s relationship with Trump. “A lot of this is rhetoric or posturing, but both sides have been careful not to fling mud,” he said.

Nevertheless, the deterioration in relations has been a major blow to South Korean President Moon Jae-in, who has staked his reputation on closer ties with North Korea. His office said it would not be daunted in this effort Friday.

“In any circumstance, our government will make efforts to resume negotiations between North Korea and the United States,” Yoon Do-han, a presidential spokesman, said in a statement.

Han Jung-woo, a deputy spokesman, said the government was watching events closely. “The current situation cannot be judged solely on Vice Minister Choe’s remarks,” he said.

Moon Chung-in, a special national security adviser to Moon, warned that signs of launch preparations could be unwise for North Korea, if it is trying to use them as leverage for negotiations.

“North Korea should avoid a butterfly effect, in which a trivial move brings a huge catastrophe,” he told a news conference in Seoul on Tuesday.

In Beijing, speaking before the North Korean news conference, Chinese Premier Li Keqiang urged patience and more dialogue between Pyongyang and Washington.

“The peninsula problem can be said to be complicated and long-standing, and it cannot be solved overnight,” Li told an annual news conference, noting that both sides had indicated they would remain in contact after Hanoi.

“We have to be patient and seize opportunities,” he said.

Washington Post writers Min Joo Kim and Gerry Shih contributed to this report.