President Trump on Thursday reassured North Korean dictator Kim Jong Un that he would remain in power under a nuclear deal with the United States, emphasizing that his administration is not seeking regime change amid threats from Pyongyang to cancel a historic summit next month.

In impromptu remarks at the White House, Trump sharply contradicted national security adviser John Bolton, who had said the administration would ask North Korea to emulate the “Libya ­model” from 2003, in which the Moammar Gaddafi regime fully relinquished its nascent nuclear weapons program.

A top Kim aide blasted Bolton this week, blaming the Libya deal for Gaddafi’s eventual downfall in an internationally backed popular uprising in 2011.

“The Libya model isn’t the model that we have at all when we’re thinking of North Korea,” Trump said. “In Libya, we decimated that country.”

By contrast, Trump added, a deal with North Korea “would be with Kim Jong Un, something where he’d be there, he’d be in his country, he’d be running his country, his country would be very rich, his country would be very industrious.”

Trump’s predecessors, including presidents Barack Obama and George W. Bush, also maintained North Korea policies that did not call for regime change. Secretary of State Mike Pompeo, who has met with Kim twice in Pyongyang over the past two months, has reportedly told him directly that the United States is not seeking his removal from power.

President Trump is scheduled to hold a meeting with North Korean leader Kim Jong Un on June 12 in Singapore. (Jabin Botsford/The Washington Post)

But Trump’s comments represented a remarkable public guarantee aimed at trying to assuage the North Koreans and ensure they would not back out of the summit, which is scheduled for June 12 in Singapore.

“If we make a deal, I believe Kim Jong Un would be very, very happy,” Trump said.

Trump and his aides have continued to insist that the Kim regime must agree to give up its nuclear program as part of any deal. But the administration has not specified a timetable or what the United States is willing to offer in return. Kim is said to be pursuing an easing of international economic sanctions, as well as other potential benefits, such as a peace treaty with the United States to formally end the Korean War and a reduction of U.S. troops in South Korea.

But some nuclear-security experts said Trump undermined his goal of reassuring Kim by appearing to confuse Bolton’s meaning about Libya and, in doing so, issuing a veiled threat to Pyongyang.

Bolton said in recent weeks that the Libya model would require North Korea to fully abandon its nuclear program before the United States would offer reciprocal benefits as occurred in the 2003 deal.

But Trump seemed focused on the overthrow of Gaddafi years later, an outcome that has led to a power vacuum and widespread chaos in Libya. Near the end of his remarks, which came in the Oval Office as he sat next to NATO Secretary General Jens Stoltenberg, Trump suggested Bolton meant that the fracturing of Libya after 2011 was what would happen to North Korea if Kim does not strike a deal.

“The best thing he could do is to make a deal,” Trump said of Kim. The Libya model “is what will take place if we don’t make a deal.”

Kingston Reif, an expert on disarmament at the Arms Control Association, predicted that Trump’s remarks would be interpreted as a threat in Pyongyang and used by hard-liners in the Kim regime as evidence that it must not take steps to reduce its arsenal.

“It runs the risk of reinforcing North Korea’s belief that it needs to hang on to nuclear weapons to seek to prevent that kind of outcome,” Reif said, referring to Gaddafi’s overthrow. “It was incredibly reckless and dangerous. North Korea will absolutely take note of it. I think it does put the summit at risk.”

Bolton, who served in the State Department and as U.N. ambassador in George W. Bush’s administration, replaced Lt. Gen. H.R. McMaster as national security adviser in April. Before taking the job, Bolton made the legal case for a first-strike military option against North Korea in a newspaper column, and he expressed deep skepticism about diplomatic talks with Pyongyang because the Kim regime had broken promises in the past.

In his statement Tuesday, Kim Gye Gwan, North Korea’s first vice foreign minister, said of Bolton: “We do not hide our feeling of repugnance towards him.”

That has led the White House to begin walking back Bolton’s comments. On Wednesday, press secretary Sarah Huckabee Sanders said the Libya model of disarmament was not being discussed inside the West Wing.

“When you’re openly disagreeing with your national security adviser on the objectives of a major negotiation, that’s going to confuse our friends and allies and maybe embolden the North Koreans,” said Michael Green, who served as senior Asia director at the National Security Council in the Bush administration.

Green said Bolton’s suggestion of a quick handoff akin to Libya’s approach is unrealistic because North Korea’s nuclear program is far more massive. But he said Bolton was “trying to lay down some markers for verifiable denuclearization.”

The fate of the summit was thrust into doubt this week after the Kim regime’s sharply worded statements and its decision to call off planned talks with South Korean officials, objecting to routine joint military exercises between South Korea and the United States.

Analysts said the actions fit with past behavior by North Korea, which has often postponed or canceled talks in an effort to gain leverage.

Trump said his administration is continuing to negotiate with Pyongyang over the specific site for the meeting in Singapore. He noted that Kim has met twice with Chinese President Xi Jinping and that the Chinese could be influencing North Korea’s position.

Trump was set to meet with the head of a Chinese government delegation that is in Washington to negotiate with the administration over trade issues.

“Nothing has changed on North Korea that we know of,” the president said. “We have not been told anything.”

White House aides rejected suggestions from reporters that Kim is in the driver’s seat. Sanders emphasized that it was Kim who extended an invitation to Trump for a meeting, which the president accepted in March. She added that if North Korea cancels the summit, the administration will continue with its “maximum pressure” policy that has relied on economic sanctions and diplomatic isolation of Pyongyang.

But analysts have said that the policy is faltering amid Kim’s diplomatic outreach to South Korea and China. South Korean President Moon Jae-in, who met with Kim last month in the demilitarized zone dividing the countries, is scheduled to meet with Trump at the White House on Tuesday.

“If the meeting happens, it happens,” Trump said of his summit with Kim. “If it doesn’t, we’ll go on to the next step.”