PALM BEACH, Fla. — President Trump has been upping the ante for his planned meeting with North Korean dictator Kim Jong Un, increasing the pressure on his administration to deliver results on an issue that has vexed his predecessors but that Trump has now embraced as his signature foreign policy initiative.

Although it remains unclear when and where the summit will take place, Trump spent much of his two-day conference here with Japanese Prime Minister Shinzo Abe this week boasting about the historic moment and ruminating on what could be achieved.

With Abe seated next to him at Mar-a-Lago, his gilded winter retreat, Trump told reporters that negotiators from North and South Korea were already at work discussing ways to bring a formal end to the Korean War, after the 1953 armistice left the divided peninsula in a perpetual state of tension. He cast the move as an appropriate appetizer for the banquet of denuclearization talks to follow.

“They have my blessing,” Trump, the self-proclaimed master dealmaker, declared. Later at a news conference with Abe, who remains wary of the sudden thaw in relations, Trump described his upcoming encounter with Kim as “a historic moment and possibly beyond that, if it works out properly.”

What has emerged in recent days is that Trump the president, who has elevated North Korea’s nuclear threat to his top foreign policy priority, is facing increasing pressure to deliver tangible results from his high-risk gambit, while Trump the showman, who is obsessed with ratings and scorecards, continues to elevate the bar of what is possible.

“We’ve gone from uncertainty about whether this summit will happen to greatly heightened expectations,” said Victor Cha, a Korea expert at the Center for Strategic and International Studies who served as a senior National Security Council official under President George W. Bush. “He’s done it himself. We’ve gone from, ‘Maybe this will happen,’ to all of a sudden talking about a peace treaty and normalization of relations.”

In many regards, a first-ever summit between a sitting U.S. president and a North Korean leader is perfectly suited to the ego of Trump, who thrilled supporters during the Republican National Convention in July 2016 when he declared, “I alone can fix it.”

Late Friday, just days before a summit next week between Kim and South Korean President Moon Jae-in, North Korea’s state news agency announced that Kim had suspended nuclear and ballistic missile tests and ordered a nuclear testing site to be shut down. The move was viewed as another sign that Kim, who last month visited Beijing in his first visit outside the country since taking office, is engaging in serious diplomacy.

Since taking office, Trump has sought to distinguish himself not just from Democratic President Barack Obama but also from Bush, a Republican. Both failed to blunt North Korea’s nuclear weapons program, but where they have fallen short, Trump believes his more un­or­tho­dox approach can achieve success.

Some Democrats have offered Trump modest praise for taking on more risk in his North Korea strategy. At an Arms Control Association conference this week, former New Mexico governor Bill Richardson, a Democrat, said Trump was making “the correct gamble” in agreeing to meet with Kim.

“As I had looked at the Korean Peninsula the last few years, things couldn’t be worse,” said Richardson, who served as the U.N. ambassador under President Bill Clinton and traveled to Pyongyang several times. “Missiles and nuclear weapons pointing at South Korea, artillery, conventional weapons. So I felt it was a risk worth taking.”

Other analysts, however, cautioned that Trump has offered no clear strategy, failing to articulate what the United States is willing to give up to the North and how the administration intends to ratify Pyongyang’s compliance with any potential disarmament deal.

Another problem, some said, was that by ramping up expectations, Trump is setting himself up not just to fall short but also to give away too much to Kim in a frantic grasp for a deal that he can sell as a win to the American public.

Several analysts suggested that Trump, in a bid to free three Americans who have been held in captivity by the North, might offer to meet Kim in Pyongyang — long considered a non-starter for a U.S. president because of security concerns and the domestic propaganda bonanza it would hand the regime.

Trump has frequently invoked the case of college student Otto Warmbier, who died last summer a few days after being released from the North in a coma after 17 months in captivity. Analysts said the president could view a return on Air Force One with the other three Americans as a dramatic denouement that obscures any setbacks in nuclear talks.

“I’m nervous that Trump is going to ignore advisers’ counsel and go to Pyongyang to rescue the detainees,” said Jung H. Pak, a former U.S. intelligence official who now serves as a Korea expert at Brookings Institution.

At his joint news conference with Abe, Trump was asked by a reporter to explain why CIA Director Mike Pompeo had returned without the three Americans from his secret meeting with Kim in Pyongyang over Easter weekend.

The president responded that his administration is “fighting very diligently to get the three American citizens back. I think there’s a good chance of doing it.” But Trump did not call their release a precondition for the summit. One U.S. government official said privately that there has been no recent signals that the release of the hostages is imminent but added that it would be highly unlikely for Trump to meet with Kim and not secure the release of the prisoners in the same meeting.

Cha, the former Bush administration official, said if Trump speaks too openly about the hostages, that would give them too much tactical value to Pyongyang, allowing the North Koreans to “feel they can give you that and nothing else.” Cha questioned whether Trump is “willing to sell the store, in the end, to say, ‘I’ve created peace; give me the Nobel Prize.’ I feel we’re headed down that path now.”

Amid criticism of his approach, Trump has sought to seize credit for what he has framed as significant progress already — forcing Beijing to clamp down on international trade embargoes against North Korea, convincing Kim to send a delegation to the Winter Olympics in South Korea and luring the North Korean leader to the negotiating table.

Trump asserted that Moon “has been very generous that without us and without me in particular, I guess, you would have to say, that they wouldn’t be discussing anything” with the North.

“Typical Trump,” said Christopher R. Hill, who led the U.S. delegation in the six-party talks with North Korea during the Bush administration. The president “tries to say, ‘Look at all this progress,’ when frankly we could have had a meeting with the North Koreans anytime.”

Moon’s administration had grown increasingly fearful that the escalating threats between Trump and Kim last year could lead to war. Pak, the former intelligence official, said the South Koreans, in a bid to tamp down Trump’s bellicose rhetoric, have worked at “creating the success story for him.”

Moon told reporters in Seoul this week that the Kim regime signaled that it would no longer demand that U.S. troops leave the Korean Peninsula that had long been a requirement from Pyongyang as part of any nuclear disarmament deal — although analysts remain skeptical.

“Those are the scaffolding that they are building leading up to the North Korea-U.S. summit,” Pak said. The South Koreans are “already creating the agenda and the crescendo of victory. Kim has never said these things before, and it can be couched as a victory. My sense is that Trump is also embracing these as victories.”

John Hudson and Carol Morello contributed to this report.