North Korea appears to believe the international community will end up recognizing it as a nuclear state, and it's important for the United States and South Korea to demonstrate that it will never be the case, a U.S. expert said Monday.

North Korean leader Kim Jong-un told the Workers' Party Congress on Sunday that he will "permanently" defend the pursuit of his trademark "byeongjin" policy" of simultaneously seeking nuclear and economic development, making clear that he has no intentions to give up nuclear weapons.

Calling the North a "responsible nuclear weapons state," Kim also said the country won't use its nuclear arms first unless its sovereignty is threatened by other countries with nuclear bombs, and will fulfill its nonproliferation obligations and push for global denuclearization.

By "global denuclearization," Kim apparently meant the North won't denuclearize unless everybody else does.

"He somehow seems to believe that the outside world will have no option other than accepting the reality of North Korea as a nuclear armed state," Jonathan Pollack, a senior fellow at the Brookings Institution, told Yonhap News Agency.

"But acknowledging that the North possesses some number of nuclear weapons and accepting North Korea as a legitimate nuclear weapons state are very different," he said. "The challenge for the U.S. and various regional actors (first and foremost the ROK) must be to demonstrate that accommodating to North Korea's preferences is simply not acceptable and will only reinforce its long-term isolation."

The expert said the North's high-profile party congress, which was convened for the first time in 36 years, showed nothing different in Pyongyang's policy, except a set of national economic goals and a five-year economic development plan Kim announced over the weekend.

"Kim seems utterly intent on defending and justifying the policies he has pursued since assuming power," Pollack said. "We'll simply have to wait to see who he installs in power near the top of the system and any clues it might offer about the future."

After the North Korean leader's address about holding on to its nuclear program, the United States urged the communist nation to abide by its own commitment as well as obligations to give up its nuclear programs under U.N. Security Council resolutions.

On Monday, the White House again urged the North to honor its denuclearization commitments.

"We have made clear that once North Korea demonstrates a commitment to coming back into compliance with those international obligations, the United States and the rest of the international community would be prepared to enter into negotiations with them and begin to give them access to the international community that they've been denied for some time now," White House press secretary Josh Earnest said.

"We give greater weight to the actions that North Korea chooses to carry out. And there are a set of specific actions that we have made clear North Korea needs to undertake, in order to escape the international isolation that they face right now," he said at a regular briefing.

Alan Romberg, a distinguished fellow at the Stimson Center in Washington, cast doubt over the North Korean leader's pledge to fulfill the country's nonproliferation obligations.

"We'll have to see. We know that the North has provided nuclear weapons help to others in the past," the expert said. "If now, due to sanctions or for other reasons, the North is seriously committed not to repeat such behavior, that would be good. But only time will tell whether Kim means it."

Richard Bush, a senior researcher at the Brookings Institution, said that Kim's address appears to be "primarily or exclusively for a domestic audience to make the case that North Korea is doing well under his leadership."

The expert also played down Kim's pledge not to use nuclear weapons first.

"The criteria that he specifies -- unless its sovereignty is encroached upon by any aggressive hostile forces with nukes -- is very wide," he said. "From the North Korean point of view, this arguably is what the United States is already doing." (Yonhap)