Washington (CNN) Secretary of State Mike Pompeo is in North Korea looking for concrete steps toward denuclearization and a timeframe for talks, but he may well leave disappointed.

Two US officials and other sources familiar with preparations for the trip say the top US diplomat is expected to get some clarity on other issues: the return of US service member remains from the Korean War, a timeline for the destruction of a missile test site that President Donald Trump said was already being dismantled and a sense of who his North Korean negotiating partner will be.

But Pompeo, who has staked his political future on efforts to dismantle the isolated country's nuclear program, may return to Washington with few details on how and when Kim will dismantle his nuclear weapons, these officials and sources say.

This forecast for Pompeo's third trip to North Korea in as many months highlights wider challenges the administration is having in pulling together a coherent approach on its greatest foreign policy challenge to date - and a growing sense of concern.

No clarity on next steps

Current officials, diplomatic sources and others familiar with internal policy discussions say the Trump administration has yet to agree with the North Koreans on a common goal or timeline, or on who will run point on detailed negotiations with Pyongyang alongside Pompeo. These sources say the situation seems characterized by a fair degree of chaos regarding next steps.

North Korean foot dragging is compounding the problem, these sources say, along with a slew of domestic challenges ranging from incomplete staffing, intelligence leaks, rivalries within the Cabinet and presidential tweets that ratchet up the pressure on Pompeo by presenting an overly rosy picture.

Administration officials familiar with the work on North Korea say they see cause for worry if Pompeo returns from this latest trip without a definite plan in hand for moving forward. There's a sense within the White House and at the State Department that they need a solid time line or some specifics on North Korea's denuclearization at the latest by the end of August.

Soon after, suspended military exercises with South Korea - which Trump and Pompeo have called "war games," using North Korean terminology - are due to start up again. There is also speculation that Trump and Kim may meet again at the UN General Assembly, which takes place every September.

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At the State Department, a senior official said Pyongyang understands the stakes, knows that Kim Jong Un needs to offer Pompeo something to prove his seriousness and do it soon.

Speaking to reporters at Yokota Air Base in Japan, on his way to North Korea, Pompeo referred to the June 12 summit in Singapore between Trump and Kim.

"Our leaders made commitments at the Singapore Summit on the complete denuclearization of North Korea and outlined what a transformed US-DPRK relationship could look like," Pompeo said. "Since the summit, the consultations have continued. On this trip I'm seeking to fill in some details on those commitments and continue the momentum towards implementation of what the two leaders promised each other and the world. I expect that the DPRK is ready to do the same."‎

After his arrival in North Korea, Pompeo met on Friday with Kim Yong Chul, the vice chairman of the country's Party Central Committee who met with Trump in Washington in May. Kim said the meeting was "very meaningful," and Pompeo agreed, saying, "I count on it being very productive." He said he had joked that "if I come one more time I'll have to pay taxes here."

Kim hinted that the process might be a long one. "The more you come, more trust we can build between one another," he said. Pompeo joked that "if I come one more time I'll have to pay taxes here."

‎But also on Friday, the research group 38 North released a report noting ongoing testing of a light water reactor, or perhaps its new operations, as well as recently completed construction. 38 North tracks North Korea's nuclear and missile program through satellite imagery.

There are any number of other challenges.

At the State Department, below Pompeo, the staffing is still unsettled and a central job - the assistant secretary for east Asia and pacific affairs - remains unfilled. Because there is no agreement with North Korean yet about the composition of delegations or structure of negotiations, officials say that Pompeo is essentially acting as the desk officer, or hands-on staffer, on Korea right now - a job that should be delegated.

One source noted that Pompeo not only is working without a fully assembled team, but that he's relatively new to this kind of role, with only a year of executive experience. And though Pompeo is devoting much of his time to the North Korea file, he is also being pushed by the White House to show progress.

Trump's tweets and declarations that things are "going well" and that "there is no longer a nuclear threat from North Korea to deal with" only ratchet up the pressure to produce results.

Pompeo has repeatedly said that Kim has promised to dismantle his weapons programs, and tweeted before he left for Pyongyang that he was "looking forward to continuing our work toward the final, fully verified denuclearization of #DPRK, as agreed to by Chairman Kim."

But defense and administration officials working on the North Korea portfolio say it's still not clear whether the US and North Korea will be able to agree on the definition and extent of that denuclearization promise.

Questions remain about whether Kim is willing to give up civilian nuclear programs, research, his missiles and warheads, or whether he would put North Korea's satellite launch program on the table as well.

Constant conflict

At every stage of negotiations, as Pompeo asks North Korea to do things, these officials say that Kim will respond by asking what he gets in return.

Pompeo also has to contend with tough opponents at home. He and national security adviser John Bolton are in constant conflict over North Korea, administration sources tell CNN.

Bolton, who has spent decades watching and working on Pyongyang, has advocated for regime change and largely been shut out of this most recent attempt at diplomacy.

While Pompeo has told CNN he won't set a timeline on talks and just needs to see continued progress, Bolton recently told CBS that the administration has set a year deadline to have Pyongyang break up all its missile and weapons programs. The comment was seen in some circles as an attempt to box Pompeo in.

"I'm sure that Secretary of State Mike Pompeo will be discussing this with the North Koreans in the near future about really how to dismantle all of their WMD and ballistic missile programs in a year," Bolton told 'Face the Nation.'

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Pompeo is also facing headwinds from a series of intelligence leaks outlining CIA and the Defense Intelligence Agency conclusions that Kim has no intention to give up his nuclear weapons anytime soon.

Trump shrugged those reports off on Thursday, speaking to reporters aboard Air Force One.

"We'll see. We'll see. All I can tell you is this. You haven't had one missile launch and you haven't had one rocket launch," he said.

He also emphasized his personal chemistry with Kim.

"I had a very good feeling about him from the standpoint - I shook his hand. I thought we got along very well. I thought we had a good chemistry together. I think we understand each other. I really believe that he sees a different future for North Korea. I hope that's true. If that's not true we'll go back to the other way," he said.

A source who recently left the administration said the intelligence leaks might be a result of frustration within the intelligence community that Trump and his secretary of state are talking up a regime that is one of the most untrustworthy and dangerous the US has ever dealt with.

'Definitively untrustworthy'

"They're probably fed up with the fact that POTUS and Pompeo keep publicly touting their trust in one of the most definitively untrustworthy regimes the US has ever negotiated with," the source said. Using Kim's initials in place of his name, the source said that the intelligence community "doesn't assess that KJU is acting in good faith."

The leaks about North Korea have generated concern at the White House and frustrated some State Department officials who suspect an attempt to undermine the President.

Within the National Security Council, there is some concern that the leaks could undermine the talks, according to the source who recently left the administration.

Most NSC staff believe that it's too early to judge the administration's progress with North Korea, given that Trump and Kim met less than a month ago. But there is worry that intelligence leaks painting Kim as unwilling to denuclearize may diminish the likelihood that he will cooperate, "if he thinks that, no matter what he does, the US has already prejudged him to be untrustworthy," the source said.

At the State Department, the senior state official called the leaks a "very curious phenomenon" that "almost seemed coordinated." The source suspected it could be out of a desire to undercut the president, but didn't know for sure.

That official said State and Pompeo are aware that the North Koreans aren't acting on denuclearization yet, but said it wasn't surprising and that Pompeo sees it as an attempt to play hardball before negotiations start in earnest.