Washington (CNN) Less than a month after President Donald Trump talked about opening "a new chapter" between the US and North Korea, the relationship between the two nations has taken a tense and hostile, but predictable turn.

In a fiery escalation, North Korea on Saturday accused the US of a "gangster-like mindset" in high-level negotiations over denuclearization, a glaring contradiction of US Secretary of State Mike Pompeo's description of the talks as "productive."

The diplomatic disconnect makes it clear that the nations are not on the same page. It calls into question the US effort to extract concessions from Pyongyang and underscores a vast difference in the way the two sides view the agreement between Trump and North Korean leader Kim Jong Un in Singapore last month.

"I think there is a fundamental misunderstanding," said CNN global affairs analyst Joseph Yun, a former top US diplomat on North Korea policy. "The US still believes North Korea will denuclearize substantially before we give them any major rewards, while North Korea believes that the two need to move together jointly, and both make concessions."

The rebuke from North Korea -- and the fact that Pompeo left the talks with little to show for his effort -- suggests that Pyongyang, and not the US, is setting the terms of negotiation. Rather than announcing any concrete achievements, the most Pompeo seemed able to deliver on Saturday was the promise of more talks.

Two US officials and other sources familiar with preparations for Pompeo's trip had said the top US diplomat was expected to get some clarity on some issues not directly related to denuclearization, including the return of US service members' remains from the Korean War and a timeline for the destruction of a missile engine test site.

But Pompeo, who has staked his political future on efforts to dismantle the isolated country's nuclear program, had little to say about remains or the missile site in his Saturday remarks to reporters. He did say that a meeting has been set up for July 12 that will involve "discussions between the folks responsible for the repatriation of remains," and that "some progress" had been made in discussing "what the modalities would look like for destruction" of the missile facility, but overall he offered few specifics.

Kim did not meet with Pompeo, a move that could be interpreted as a snub, though his spokesman said that was never an expectation. Instead, the top US diplomat met on Friday and again on Saturday with Kim Yong Chol, the vice chairman of the country's Party Central Committee.

On Saturday, Pompeo insisted to reporters that "the complete denuclearization of North Korea" remains the objective, and "no one walked away from that," adding, "Chairman Kim is still committed." But in response to a reporter's question over whether the US is moving closer to firming up a timeline for denuclearization, he said, "I'm not going to get into the details of our conversations."

Despite the contradictory take on the discussions, a spokesman for North Korea's foreign ministry said toward the end of a lengthy statement Saturday, "We still cherish our good faith in President Trump."

Yun said Pyongyang seemed to have the advantage in the talks at the moment.

"So far, it appears that North Korea has gained more than the US," he said, adding, "it looks like North Korea is dictating the pace and the direction of the talks."

The outcome of the most recent talks underscores the challenging situation Pompeo is in as he attempts to turn Trump's vague rhetoric into reality with one of the toughest and most recalcitrant negotiating partners on the global stage. North Korea has stymied other administrations with a combination of contradiction, subterfuge and mixed messaging -- and is playing true true to form.

has repeatedly insisted must take place. The US may have backed itself into a corner early on as a result of Trump's agreement to meet with the North Korean leader for a historic summit last month without first extracting a formal pledge of "complete," "verifiable" and "irreversible" denuclearization, which the administration

Instead, the US received only a vague assurance from North Korea last month that it would "work toward complete denuclearization of the Korean Peninsula."

In the meantime, satellite images indicate that North Korea has made upgrades to a nuclear facility and researchers in the US have said that it also appears to be finalizing the expansion of a ballistic missile manufacturing site.

Defense and administration officials working on the North Korea portfolio say it's still not clear whether the US and North Korea will even be able to agree on the definition and extent of what "denuclearization" means. Leaked information has revealed that the Defense Intelligence Agency doesn't think Kim has any intention of giving up his nuclear weapons anytime soon.

Current officials, diplomatic sources and others familiar with internal policy discussions say the administration has been having trouble pulling together a coherent approach for dealing with North Korea, and that there is a growing sense of concern.

These sources 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.

Administration officials familiar with the work on North Korea had told CNN they saw cause for worry if Pompeo returned from this trip -- his third to North Korea in as many months -- without a definite plan in hand for moving forward.

They say there's a sense within the White House and at the State Department that they need a solid timeline or some specifics on North Korea's denuclearization by the end of August at the latest.

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 United Nations General Assembly, which takes place every September.

Such a meeting, or even a return trip by Pompeo to Pyongyang, would be hard for the administration to agree to without some tangible progress.