SEOUL, South Korea — For months, North Korea’s leader, Kim Jong-un, has been unexpectedly conciliatory toward South Korea and the United States, announcing a halt to nuclear and missile tests even as the two countries staged military exercises that the North sees as a rehearsal for invasion.
Then on Wednesday, North Korea said Mr. Kim’s government would not give up its nuclear weapons unless Washington removed military threats against his isolated country. Without such assurances, it said Mr. Kim could withdraw from a planned June 12 summit meeting with President Trump in Singapore.
“North Korea wanted to show that threatening to walk away from a meeting is a negotiating tactic it has mastered long before President Trump did,” said Lee Byong-chul, a senior fellow at the Institute for Peace and Cooperation in Seoul.
If North Korea’s tough statements on Wednesday caught officials in Seoul and Washington off guard, they also reflected a well-established North Korean stance.
Even as he has recently reached out to Washington and Seoul for dialogue, Mr. Kim has repeatedly said he would denuclearize his country only if it no longer felt “threatened militarily” by such exercises as the “Max Thunder” Air Force drills underway now between the United States and South Korea. He has also demanded “security guarantees” from the United States, and said his country wants to enter talks with Washington as an equal nuclear power.
”The last thing Kim Jong-un can afford is to look like he is surrendering his nuclear weapons,” said Koh Yu-hwan, a professor of North Korean studies at Dongguk University in Seoul. “Countries need to help North Korea find a way to disarm itself in a face-saving way.”
North Korea grew nervous that it might look weak by making unilateral concessions, like the missile-test moratorium and its decision to shut down its nuclear test site, while the United States has not matched them with its own concessions and only vowed to keep up its maximum pressure, Mr. Koh said.
Few analysts said the North would ultimately go so far as to cancel the Singapore meeting. Rather, the threat to withdraw was an attempt to raise the price that Washington would have to pay to get any significant concessions on the North’s nuclear program, analysts said.
“The goal is to change the subject from what the U.S. wants to talk about — denuclearization — to Pyongyang’s preferred focus: U.S. military exercises, the U.S. ‘threat’ and by extension the U.S.-South Korea alliance,” said Evans J.R. Revere, who directed Korean policy at the State Department during the administration of President George W. Bush.
North Korea’s abrupt change in tone began Wednesday when it indefinitely postponed high-level talks with South Korea, blaming the joint military drills with the United States that began last week.
Hours later, the North’s first vice foreign minister, Kim Kye-gwan, attacked Mr. Trump’s hawkish new national security adviser, John R. Bolton, for demanding that North Korea quickly dismantle its nuclear facilities and ship them out, as Libya did more than a decade ago, before the United States lifts sanctions and provides other benefits.
That demand clashes with the North’s stated strategy. When Mr. Kim met with China’s president, Xi Jinping, twice in the last two months, he sought support for his country’s longstanding demand that Washington and its allies take “synchronized” steps to satisfy the North’s security needs in return for any “phased” moves toward denuclearization.
North Korea turned to China because as the North’s biggest economic benefactor, it can provide the best economic and political cover as Mr. Kim confronts Mr. Trump over his demands.
When South Korea’s leader, Moon Jae-in, met China’s premier, Li Keqiang, in Tokyo a week ago, the two urged Washington to address North Korea’s concerns about its long-term security.
The two leaders agreed that “rather than asking North Korea to make unilateral concessions, the international community, including the United States, should actively participate in guaranteeing a bright future for the North, including security guarantees and assistance for economic development, if it denuclearizes completely,” Mr. Moon’s office said at the time.
But Mr. Trump has yet to clarify how he would reconcile the North Korean demand with his own push to quickly achieve a “permanent, verifiable and irreversible denuclearization” of North Korea. Instead, his top aides have sent out confusing signals.
Secretary of State Mike Pompeo, who met with Mr. Kim twice in Pyongyang in recent weeks, said that if North Korea took bold action to denuclearize quickly, “the United States is prepared to work with North Korea to achieve prosperity on the par with our South Korean friends.”
“We will have to provide security assurances, to be sure,” Mr. Pompeo said. “This has been a trade-off that has been pending for 25 years.”
But Mr. Bolton was more blunt, calling for “getting rid of all the nuclear weapons, dismantling them, taking them to Oak Ridge, Tenn.,” where the Department of Energy operates a nuclear complex and Libya’s dismantled nuclear program ended up. He said that if the North Koreans “want to become a normal nation like South Korea, the quicker they denuclearize, the quicker that will come.”
Analysts say the Americans were sending mixed signals to the North.
“North Korea is upset how Trump is playing it — Pompeo playing the good cop and Bolton the bad cop,” said Kim Dong-yub, an analyst at the Seoul-based Institute for Far Eastern Studies in Seoul.
North Korea’s fierce antagonism toward Mr. Bolton vividly illustrates its deep mistrust of the United States. When Mr. Bolton was under secretary of state in Mr. Bush’s administration, he called the North’s Kim dynasty “tyrannical.” North Korea returned the insult, calling him “human scum.”
Mr. Bolton’s attacks have been deeply insulting to the Kim government, which portrays its leader as a godlike figure, analysts said. Although Mr. Kim keeps his hard-line military under tight control, appearing weak in a confrontation with Washington could be devastating to his image among his soldiers, who consider the United States their archenemy.
Mr. Kim’s government has told its people that his nuclear weapons will protect them from suffering the fate of Libya or Iraq, whose governments collapsed under pressure from “big powers,” in Pyongyang’s words. At the same time, Mr. Kim has promised his people they will not have to tighten their belts again as he seeks to get sanctions lifted so he can rebuild the economy.
Cheon Seong-whun, an analyst at the Asan Institute for Policy Studies in Seoul, said North Korea’s main goal in coming negotiations with the United States was to “weaken the influence of American forces in Korea.”
One aim is to try to stop the United States military from bringing nuclear-capable aircraft or vessels to Korea. That was why on Wednesday the North vehemently protested South Korean news media reports that American B-52 long-range bombers and F-22 stealth fighter jets participated in the current drills, Mr. Cheon said.
The United States military denied the participation of B-52s, saying that Washington and Seoul had decided not to include them in the exercises “some time ago,” said Col. Chad Carroll, a spokesman for American forces in South Korea. But the participation of F-22 stealth jets will not be affected by the North Korean protest, the South’s military said.
In China, analysts said that Mr. Kim’s about-face was a return to his normal behavior. The trajectory of the past several months was uncharacteristic, they said.
”Kim Jong-un has been soft like a dove, but he also has a side to him like an eagle,” said Wu Qiang, a writer on current affairs and former lecturer at Tsinghua University. “This change of mind is more normal.”
Choe Sang-Hun reported from Seoul, and Jane Perlez from Beijing. Motoko Rich contributed reporting from Tokyo.