Still, Mr. Trump conspicuously declined to make their release a precondition of his meeting with Mr. Kim. He also did not demand any new concessions from North Korea beforehand, underscoring how determined he is to make history by convening with the leader of a country he threatened with war a few months ago.
In preparing for the planned event, Mr. Trump’s decision to dispatch his C.I.A. director reflected the president’s trust in and comfort with Mr. Pompeo, as well as how diplomats were sidelined in brokering what could be a landmark encounter.
“Meeting went very smoothly and a good relationship was formed,” Mr. Trump said in an early morning Twitter post before he went golfing with Mr. Abe. “Details of Summit are being worked out now. Denuclearization will be a great thing for World, but also for North Korea!”
Mr. Pompeo is still awaiting confirmation to his new post, and faces a challenging vote in the Senate Foreign Relations Committee, where several Democrats have come out against him. The White House and Republicans seized on Mr. Pompeo’s trip as another reason for the Senate to confirm him, while Democrats said he had misled them by failing to disclose his mission, even in private conversations.
But the visit underlines the confidence that Mr. Trump has developed in Mr. Pompeo, a former Tea Party congressman who has emerged as one of the president’s closest advisers — a stark contrast to Rex W. Tillerson, whom Mr. Trump fired as secretary of state days after he accepted Mr. Kim’s invitation to meet.
It also underlines Mr. Trump’s unorthodox approach to one of the riskiest diplomatic gambits of his presidency. However trusted by the president, Mr. Pompeo is hardly a traditional emissary. He is not yet the nation’s chief diplomat but a lame duck as the nation’s spymaster.
Mr. Pompeo met with Mr. Kim on Easter Sunday, a senior official said, bringing along several aides from the C.I.A. — but nobody from the State Department or the White House.
Some former administration officials expressed surprise that he returned from Pyongyang with no visible concessions, like the release of the three Americans detained in North Korea. Mr. Pompeo raised the issue, another official said, adding that the White House would continue to push for their release.
In 2014, James R. Clapper, then the director of national intelligence, traveled secretly to North Korea to negotiate the release of two Americans, Kenneth Bae and Matthew Todd Miller. Three Korean-Americans — Kim Dong-chul, Kim Sang-duk and Kim Hak-song — are currently being held on charges of espionage and committing hostile acts toward the North Korean state.
The administration also has not agreed on a date for the meeting between Mr. Trump and Mr. Kim, which officials said pointed to problems in settling on a site for the encounter. On Tuesday, Mr. Trump told reporters that the White House was looking at five potential locations.
The White House has begun narrowing the list of options, a senior official said, eliminating sites like Pyongyang and the Demilitarized Zone between North and South Korea, which could pose an optics problem for Mr. Trump. Meeting somewhere in the United States remains a possibility, though that could raise similar issues for Mr. Kim.
Credit
Doug Mills/The New York Times
The administration is studying several third countries — Singapore and Vietnam, in Asia; Sweden and Switzerland, in Europe — though all are far from North Korea, posing a challenge to Mr. Kim’s fleet of rickety aircraft. Mongolia, which is closer to the North, is a long shot, the official said.
Without a site, however, the White House has been unable to announce a date, though officials are sticking to Mr. Trump’s recent declaration that the meeting will be in late May or early June.
On Tuesday, Mr. Trump added to the mystery surrounding the visit by appearing to confirm that he had been in direct contact with Mr. Kim himself. He later clarified that while the talks were at “the highest levels,” he would “leave it a little bit short of that.”
Mr. Pompeo’s involvement with North Korea predated Mr. Trump’s decision to meet Mr. Kim, several officials said. He has been dealing with North Korean representatives through a channel that runs between the C.I.A. and its North Korean counterpart, the Reconnaissance General Bureau.
He also has been in close touch with the director of South Korea’s National Intelligence Service, Suh Hoon, who American officials said brokered Mr. Kim’s invitation to Mr. Trump.
While a meeting between the leaders would be one of the boldest diplomatic gambles in recent years, it was orchestrated largely by the intelligence services of the three countries.
Officials said Mr. Suh laid the groundwork for Mr. Kim’s invitation in negotiations and a subsequent meeting in Pyongyang with Kim Yong-chol, a powerful general who leads inter-Korean relations and used to run North Korea’s intelligence service.
Mr. Suh was one of two South Korean envoys who visited the White House to brief Mr. Trump on their meeting with Kim Jong-un in Pyongyang — which led to the president’s impromptu decision to accept Mr. Kim’s invitation.
For Mr. Pompeo, who now has an office at the State Department, the choice to use the intelligence channel was mostly a convenience — allowing him to be involved in the planning as he awaited his move to the department.
Still, some officials expressed concern that the C.I.A. had taken the lead in orchestrating a leader-to-leader meeting — work that would normally fall to the State Department. The intelligence officials on the North Korean side, they said, are shadowy figures, not least Kim Yong-chol himself, who is accused of masterminding a torpedo attack that sank a South Korean Navy ship in 2010, killing 46 sailors.
The State Department’s role in North Korea dwindled after Mr. Trump publicly split with Mr. Tillerson over his efforts to open a diplomatic channel to the North, initially to obtain the release of the three Americans but also to set the stage for a broader negotiation.
In October, while Mr. Tillerson was in Beijing, Mr. Trump tweeted, “I told Rex Tillerson, our wonderful Secretary of State, that he is wasting his time trying to negotiate with Little Rocket Man…”
The State Department recently lost its chief North Korea negotiator, Joseph Yun, who retired from the Foreign Service, in part because of his frustration with his agency’s diminished role.
The timing of Mr. Tillerson’s departure, officials said, was not coincidental. Mr. Trump wanted to have Mr. Pompeo in place to oversee an opening to North Korea. But Mr. Pompeo has expressed extremely hawkish views about North Korea, suggesting over the summer that the United States should push for regime change.
“It would be a great thing to denuclearize the peninsula, to get those weapons off of that, but the thing that is most dangerous about it is the character who holds the control over them today,” Mr. Pompeo said at the Aspen Security Forum. “So from the administration’s perspective, the most important thing we can do is separate those two.”
Last week, Mr. Pompeo insisted to the Senate Foreign Relations Committee that he had never advocated such change.
“Just to be clear, my role as a diplomat is to make sure that we never get to a place where we have to confront the difficult situation in Korea that this country has been headed for now for a couple of decades,” he added.
