WASHINGTON - North Korea's insincerity toward denuclearization and its demand for greater U.S. concessions are making the possibility of serious working-level talks with Washington dim, experts say.

"I don't think there is much prospect for real progress in dismantling (North Korea's) nukes," said Robert Manning, a senior fellow at the Atlantic Council. "It's possible Kim Jong Un will order (his negotiating team) back to the table, have several more sessions, so there's an appearance of sincerity."

The long-stalled working-level talks between Washington and Pyongyang resumed Saturday in Stockholm and ended unsuccessfully without making any progress toward denuclearization.

Evans Revere, a former State Department official who had negotiated with North Korea extensively, thinks the talks broke down because Pyongyang intended to reject a U.S. offer and demand greater concessions.

"North Korea came to the Stockholm talks planning to listen to the U.S. proposal, reject them as inadequate and then leave for home with a demand that the U.S. make a fundamental shift in its position if it hopes for talks to resume," he said.

Exploiting Washington

Pyongyang's goal, according to Revere, is to pressure the U.S. to make more concessions by exploiting Washington's desire to hold denuclearization talks more than it does.

While it is uncertain what specific offers Washington made and concessions Pyongyang demanded at their Stockholm meeting, the U.S. said in a statement released shortly after the abrupt end of the talks that it brought "creative ideas" and presented "a number of new initiatives."

In a statement issued through its official Korean Central News Agency (KCNA) on Sunday, Pyongyang said, "At the negotiations, the U.S. side maintained its former stand, seemingly showing that it has brought no new package."

Ken Gause, director of the Adversary Analytics Program at CNA research center, thinks Pyongyang will not reopen negotiations unless the U.S. makes substantial concessions.

"The U.S. did not put anything on the table," said Gause. "Without upfront concessions, North Korea has nothing to negotiate over. It will not make the first concessions."

The Stockholm talks were held after months of an impasse between the two sides since the failed Hanoi Summit in February. In Hanoi, North Korean leader Kim Jong Un conveyed that he wanted sanctions relief, and offered to dismantle a part of North Korea's nuclear facilities.

U.S. President Donald Trump denied Kim's offer and asked for full denuclearization in return for sanctions relief.

Working-level talks had been stalled since the Hanoi summit, until the countries met in Stockholm as Kim promised that North Korea would resume talks when he met with Trump at the inter-Korean border of the demilitarized zone (DMZ) in June.

Manning thinks North Korea met with the U.S. in Stockholm to show that it held up to its promise but never intended to make any serious negotiations on denuclearization.

"I think this was about Kim having to keep his DMZ pledge to allow working-level talks," said Manning. "So, the talks (are a way) to check the box."

To gain concessions

Dennis Wilder, the National Security Council's senior director for East Asian Affairs during the George W. Bush administration, believes Pyongyang walked away from the talks believing it could gain more concessions from Trump.

Wilder said Pyongyang thinks Trump will likely grant more concessions because it believes he is in a vulnerable position domestically, being under an impeachment probe while campaigning for reelection.

"The U.S. side apparently placed a new proposal on the table, and the North may believe that by rejecting it out of hand and making new threats, it can strong-arm President Trump," said Wilder. "The North may be overestimating the Trump administration's vulnerability at this time and could make a serious miscalculation."

Washington and Pyongyang gave two different views of their meeting and future talks hosted by the Swedish government. The U.S., in its statement, said it had "good discussions" with North Korea. The U.S. said it has accepted the Swedish government's invitation to return to Stockholm to meet with Pyongyang in two weeks.

By contrast, North Korea, in its statement, threatened it will not meet with Washington until it took "a substantial step" toward its "withdrawal of hostile policy" that "threatens the security of the country."

Pyongyang refused the Swedish invitation for another round of working-level talks. Referring to the talks as "sickening," Pyongyang said Washington was "misleading the public opinion" by calling the talks productive.

Revere said the difference highlights Pyongyang's unwillingness to denuclearize.

"This difference, in my view, is driven by the fact that North Korea has no intention of agreeing to Washington's definition of denuclearization, because it has no intention to denuclearize," said Revere.

Differing denuclearization definitions

Washington's definition of denuclearization has been the complete dismantlement of North Korea's nuclear arsenal and program, which is different from North Korea's definition of removing the U.S. nuclear umbrella from the Korean peninsula.

Bruce Klingner, former CIA deputy division chief of Korea and current senior research fellow at the Heritage Foundation, said, "While some will dismiss North Korea's comments as diplomatic maneuvering, they are consistent with repeated missives this year, and indeed, decades of resistance to abandoning its nuclear arsenal."

North Korea said several times this year it will give the U.S. until the end of the year to change its position that it can accept.