South Korean Foreign Minister Kang Kyung-wha speaks during a U.N. Security Council meeting Thursday. (Brendan McDermid/Reuters)

South Korea is proposing that the United States hold off on a demand for an inventory of North Korea’s nuclear weapons and accept the verified closure of a key North Korean nuclear facility as a next step in the negotiations, Seoul’s top diplomat said in an interview with The Washington Post.

The plan is designed to break the impasse between North Korea and the United States as President Trump comes under mounting pressure to demonstrate progress on the denuclearization talks. It will be one of the options available to Secretary of State Mike Pompeo as he arrives in North Korea on Sunday to restart negotiations.

In exchange for the verified dismantlement of the Yongbyon nuclear facility, the United States would declare an end to the Korean War, a key demand of Pyongyang that U.S. officials have been reluctant to make absent a major concession by North Korea.

“What North Korea has indicated is they will permanently dismantle their nuclear facilities in Yongbyon, which is a very big part of their nuclear program,” South Korean Foreign Minister Kang Kyung-wha said during a discussion at the South Korean mission to the United Nations. “If they do that in return for America’s corresponding measures, such as the end-of-war declaration, I think that’s a huge step forward for denuclearization.”

Sustained fighting in the Korean War ended with a truce in 1953, but a formal peace treaty has never been signed. In recent weeks, North Korea has demanded almost daily that the United States sign an end-of-war declaration.

U.S. negotiators have tried to get North Korea to provide a list of nuclear facilities and weapons they want dismantled but failed to secure an agreement even after Trump’s meeting with North Korean leader Kim Jong Un in Singapore and three trips to North Korea by Pompeo.

On Tuesday, North Korea’s state-run broadcaster again called the demands for a nuclear inventory “rubbish.”

Kang said demanding a list at the outset risks bogging down the negotiations in a subsequent dispute over verification. As an example, she cited the deterioration of negotiations between North Korea and the George W. Bush administration after Pyongyang handed over thousands of pages of documents on its main plutonium-related facilities in 2008.

“The past experience shows that the list and the verification about the list takes a lot of back-and-forth, and I think the last time things broke down precisely as we were working out a detailed protocol on verification after we had gotten the list . . . We want to take a different approach,” she said.

Stressing the importance of stopping the further production of nuclear materials at the Yongbyon facility, she added: “We will have to see an inventory at some point, but that some point can be reached more expeditiously by action and corresponding measures that give the two sides sufficient trust.”

Whether Seoul can persuade Washington to take up the proposed bargain remains to be seen. The State Department declined to comment on its willingness to delay demands for an inventory or declare an end to the Korean War.

Hawks inside the Trump administration, in particular national security adviser John Bolton, remain skeptical of signing such a declaration out of fear that it will give North Korea and China justification to demand the removal of the 28,500 U.S. forces stationed in South Korea, people close to Bolton said, speaking on the condition of anonymity to discuss the sensitive negotiations.

Kang downplayed concerns about the declaration, emphasizing that it would be a purely “political” document and “not a legally binding treaty.”

Trump, according to diplomats familiar with the negotiations, is open to signing the declaration and may not be bothered by ensuing demands about U.S. forces given his long-standing complaint that the United States pays far too much to station troops in East Asia.

Analysts briefed on South Korea’s proposal offered mixed assessments.

“If the Yongbyon shutdown proves to be the first bite of the apple, it might be an okay starting point, but if it proves to be the only bite of the apple, it will be deeply unsatisfying — and totally reversible,” said Scott Snyder, a Korea expert at the Council on Foreign Relations.

Duyeon Kim, a Korea expert with the Center for a New American Security, said the closure of Yongbyon would be a “welcome” and “tangible” step but noted that North Korea would still be able to expand its nuclear arsenal and fissile material production at covert facilities elsewhere in the country.

“It’s unrealistic to expect a comprehensive, completely accurate list from the get-go, but the administration should still insist that Pyongyang at least disclose all fuel-cycle-related facilities anywhere in the country,” she said.

On Tuesday, State Department spokeswoman Heather Nauert said Pompeo would arrive in North Korea on Sunday but gave few details about the status of the negotiations. “Obviously these conversations are going in the right direction and we feel confident enough to hop on a plane to head there to continue the conversations,” she said.

The U.S. outlook on the negotiations has been difficult to surmise as Trump hails major accomplishments going on behind closed doors, while Pyongyang falls short of key U.S. demands, including providing its understanding of denuclearization and the number of weapons and amount of bomb fuel it has.

“If you saw what’s going on behind the scenes, I think you’d be very impressed,” Trump said last week. “I’ve received two letters from Chairman Kim . . . They’re letters that are magnificent in the sense of his feeling for wanting to get this done.”

North Korea has already signaled that it may drive a hard bargain during Pompeo’s fourth visit. Despite calling for the end-of-war declaration, the Korean Central News Agency said Tuesday that the document “can never be a bargaining chip for getting the DPRK denuclearized” and that the United States must ease economic sanctions before North Korea takes steps.

“If the U.S. doesn’t want the end of war, the DPRK will also not particularly hope for it,” the news agency said in a commentary.

The North has also given Pompeo’s new special representative for North Korea, Stephen Biegun, the cold shoulder, said U.S. officials, who also spoke on the condition of anonymity to discuss the sensitive talks. Last month, Pompeo publicly invited Pyongyang to meet with Biegun in Vienna at the “earliest opportunity,” but the request went unanswered and the North has yet to name a counterpart for Biegun, they said.

Kang, South Korea’s first female foreign minister, is trying to build momentum behind the U.S.-North Korea talks despite international skepticism that Kim is willing to surrender his nuclear arsenal.

In the process, she and South Korean President Moon Jae-in have fended off allegations of naivete from Japanese and American counterparts who say their belief in dialogue blinds them to Kim’s deceptive nature.

Kang said her government has no illusions about the nature of the Kim dynasty, a fact that guides her thinking on negotiating tactics.

“We know North Korea better than any party in this process,” she said. “We are as keen and perhaps as committed as anybody on getting to complete denuclearization . . . Naivete is certainly not something that would characterize my government’s approach to North Korea.”

Moon, a former human rights lawyer, and Kang, a former U.N. deputy high commissioner for human rights, have both come under pressure to underscore human rights violations in North Korea, which is accused of incarcerating tens of thousands of citizens in labor camps dedicated to political crimes among many other abuses.

Kang said Seoul supports efforts by the international community to advance human rights in North Korea but acknowledged that denuclearization is the most paramount concern for her country.

“The North Korean human rights situation is a global issue, and we are part of the global discussions,” she said. “There are times to raise these issues. Certainly not at this time, when we very much need to move forward on the denuclearization issue.”

Trump, whose advisers initially sought a quick deal with North Korea, told reporters last week he's in no “rush.”

Kang said the remarks reflect the complexity of the negotiations. “I think there is a lot more understanding and appreciation of the difficulty of the issue,” she said. “This is a very advanced program, so you can’t just dismantle it or do away with it in a matter of a short period.”