(CNN) The last time a US official of CIA director Mike Pompeo's stature visited North Korea was in 2014, when then-Director of National Intelligence James Clapper went to secure the release of two Americans held prisoner . There, Clapper met with low-level officials.

This time however, Pompeo traveled to Pyongyang and met with leader Kim Jong Un himself, a move that appears to signify both sides' commitment to have a summit and discuss denuclearization on the Korean peninsula, and giving Kim the presidential audience he's craved.

To meet with a sitting US President has been a long-held ambition of the Kim family. For US President Donald Trump however, the nearer the summit approaches, the harder it will be to back out

On Tuesday evening, after receiving Japanese Prime Minister Shinzo Abe at his Mar-a-Lago resort in Florida, Trump attempted to give himself a little leeway.

"It'll be taking place probably in early June, or a little before that, assuming things go well," Trump told reporters. "It's possible things won't go well, and we won't have the meetings and we'll just continue to go along this very strong path that we've taken. But we'll see."

The possibility that Trump may be able to walk away at the last minute was made even harder on Wednesday, when North Korea announced that Chinese President Xi Jinping was preparing to visit Pyongyang "soon," according to an official with knowledge of ongoing discussions between the two countries.

The official added that Russia has also requested a summit with Kim, but the North Koreans have yet to respond.

Pompeo returned empty-handed

The news of Pompeo's meeting with Kim, which occurred over Easter weekend (sometime over the end of March and the beginning of April) also raised eyebrows that unlike Clapper, Pompeo went to North Korea and didn't come back with Americans being held captive by the isolated regime.

"It's strange to see the nominee for Secretary of State come and go from Pyongyang without securing the release of the three Americans imprisoned there," said Adam Mount, senior fellow and director of the Defense Posture Project at the Federation of American Scientists, where he covers US nuclear strategy, deterrence and North Korea. "I expect they will be released, but the United States should not pay a price for their freedom."

There are three Americans currently being held in North Korea. Kim Hak-song and Kim Sang-duk -- also known as Tony Kim -- were imprisoned in 2017 on suspicion of "hostile acts." Kim Dong Chul was arrested in 2015 and has been serving a 10-year sentence on espionage charges. Sweden has been helping to negotiate their release

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Their continued detention is another sign that moves for a summit have been progressing without any real concessions by the North Koreans, which might give South Korea and its partners confidence that Pyongyang was serious about denuclearization.

"South Korea is pushing so quickly and so fast because they want to move as far away from talk about military options or preemptive strikes and so maybe that's what ends up making them appear so eager and optimistic to accept any proposal the North Koreans toss out there," said Lisa Collins, a fellow at the Office of the Korea Chair at the Center for Strategic and International Studies in Washington DC.

South Korean President Moon Jae-in campaigned on a platform to reengage with the North, she said, "they were just looking for the opportunity and now that they have the ball they're sprinting with it."

"Usually a summit like this would include experienced diplomats, after months of preparation and North Korea had made substantial concessions," said Mount. "The meeting is itself a significant win for a regime that the United States was working to isolate."

Of five likely locations, none are in the US

An administration official familiar with Pompeo's meeting with Kim said the North Korean leader was "personable and well prepared" for the discussion, but the main sticking point at that time was the venue for the summit between Trump and Kim.

President Trump revealed Tuesday as he met with Abe that five different locations were under discussion as possible venues for the meeting.

Some of those floated by American officials over the past month include the Mongolian capital of Ulaanbaatar, the Demilitarized Zone (DMZ) between South and North Korea, a neutral European capital like Stockholm or Geneva, or a Southeast Asian nation like Singapore or Malaysia.

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Pyongyang was an unlikely option since it would almost certainly be used as a propaganda opportunity by the North Koreans. Seoul, too, is in the mix.

Prior to the news that Pompeo had gone to Pyongyang came out, Trump had dropped hints about top level talks between the two countries during his joint press conference with Abe. Trump said "very high levels" of discussion between Washington and Pyongyang were already underway.

"We have had direct talks," he said. The White House later clarified Trump's comments to make it clear he has not yet talked directly with Kim.

Peace in Trump's time?

Trump's mention during the briefing of North and South Korean officials discussing "an end of the war" will certainly require an American presence should such negotiations actually succeed.

It was the US, and not South Korea, that signed the armistice with North Korea in 1953. Trump told reporters he supported the discussions.

"And they do have my blessing to discuss the end of the war," he told reporters on Tuesday. "People don't realize the Korean War has not ended. It's going on right now and they are discussing an end to the war."

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Another reason that would likely factor in Trump's inability to walk away from a meeting with Kim: it might bring about some kind of arrangement for a peaceful solution for the peninsula. That would be a huge political win for his presidency.

Trump has already claimed credit for the peace the Koreas have experienced so far this year. He said his leadership prevented military confrontations during the Winter Olympics that were held in South Korea in February. And he pointed to praise from Moon , Abe and others as proof of his skills.

"They've 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, including, the Olympics would have been a failure. Instead it was a great success," Trump said on Tuesday.

"They would have had a real problem. But as you know North Korea participated in the Olympics and ... it was quite a success. That would not have happened."