NEW YORK — South Korean Foreign Minister Chung Eui-yong is calling on the U.S. government to detail more specific incentives it might offer North Korea in face-to-face negotiations, warning the Biden administration that Pyongyang is using the long-stalled talks to improve its missile and nuclear capabilities.

“If we let the status quo continue, it will lead to the strengthening of North Korean missile capabilities,” Chung said during an interview at the South Korean mission to the United Nations in New York. “We are very concerned about it.”

Chung’s remarks came on the sidelines of the U.N. General Assembly last week, where North Korea’s top diplomat accused the Biden administration of hostility and demanded that it end military exercises with South Korea.

Days later, North Korea hailed the testing of a “hypersonic missile” and an antiaircraft missile, its third and fourth round of launches in September.

Negotiations aimed at ending North Korea’s nuclear program have been frozen since February 2019. The Biden administration has said it will meet with North Korean officials anytime, anywhere, without preconditions, to discuss denuclearization. Pyongyang insists on the lifting of U.S. sanctions while claiming the right to develop its nuclear weapons program, which North Korean leader Kim Jong Un considers a deterrent to U.S. aggression.

South Korean President Moon Jae-in has tied his legacy to improving relations with North Korea. But with only one year left in his tenure and little progress to show on a denuclearization deal, his desire to resume talks between Washington and Pyongyang has become more acute.

Chung said the two main impediments to talks was “distrust” between the two sides and North Korea’s self-imposed isolation as it tries to prevent the spread of the coronavirus.

“Distrust cannot be overcome with a single stroke,” he said. He recommended that the Biden administration spell out the “concrete things” it can offer North Korea at the negotiating table, such as a declaration that would formally bring an end to the 1950-1953 Korean War, which concluded with a cease-fire rather than a peace deal.

A senior U.S. official rejected the idea that the Biden administration has not offered specifics to the North Koreans, blaming the stalemate on Pyongyang’s lack of response to U.S. overtures.

“We are seeking serious and sustained diplomacy with the DPRK and are prepared to meet without preconditions,” said the official, who spoke on the condition of anonymity to discuss diplomatic efforts. “In our outreach we have made specific proposals for discussion with the DPRK but have not received a response.”

Analysts worry that North Korea may be attempting to substitute direct talks for a high-level summit, which did not produce results during President Donald Trump’s three meetings with Kim.

“It will be very problematic if North Korean negotiators are not allowed to discuss the nuclear issue with President Biden’s envoy, Sung Kim, as was the case during the Trump years,” said Duyeon Kim, a Korea expert at the Center for a New American Security.

“Pyongyang needs to empower its negotiators and allow negotiations to function properly, rather than trying to force a summit from the get-go.”

In an effort to improve the atmosphere for talks, Moon pushed for an end-of-war declaration during his speech last week at the U.N. General Assembly. But the offer was rebuffed by Kim Yo Jong, the North Korean leader’s powerful sister, who said the proposal was an “interesting and an admirable idea” but premature.

Critics of Moon have said his pursuit of better relations with North Korea is naive. They say the North only pursues dialogue in the hopes of sanctions relief and has never been serious about denuclearization.

“Moon Jae-in’s government should not try to rush for an outcome that they can use for the upcoming election,” Lee Jun-seok, the chairman of South Korea’s opposition People Power Party, said in an interview. “We now know that even with the two inter-Korean summits [between Moon and Kim], nothing really changed during the Moon Jae-in administration, so we believe that another inter-Korean summit or an end-of-war declaration is unlikely to bring any change in inter-Korean relations.”

Kim announced on Thursday that a cross-border communication line with South Korea would be restored in early October. In a speech before the country’s rubber-stamp parliament, Kim said the restoration of ties, which had been largely dormant for more than a year, would contribute to the Korean people’s wish for peace and security.

When asked about Kim’s hotline remarks, Secretary of State Antony Blinken told reporters on Thursday that “if there are any measures that can appropriately reduce the risk that exists, that probably makes sense.” He added that the agency remains “very concerned” about North Korea’s missile launches, which amount to “repeated violations” of U.N. Security Council resolutions.

Chung said North Korea’s concerns about the spread of the coronavirus have fueled its opposition to engagement. “It’s one of the main reasons,” Chung said. “They are afraid of outside contact.”

This has resulted in problems for countries trying to send supplies and diplomatic personnel to their embassies in Pyongyang, he said. China, for instance, appointed a new ambassador to North Korea this year, but he has been unable to travel to the country.

Kim has also turned down foreign vaccine donations offered by a U.N.-backed immunization program, worrying world health officials. Chung said Seoul has communicated that it is willing to help North Korea with a coronavirus response. One reason Pyongyang may have rejected the vaccine, he said, is that it doesn’t have the medical infrastructure to disseminate the shots “and they know it.”

Meanwhile, questions remain about what North Korea claims was its first-ever hypersonic missile launch. One person close to the South Korean government said Seoul is still analyzing the trajectory of the missile but thinks it is an extension of existing missiles such as Hwasung 7 and Hwasung 9, which use liquid fuel.

U.S. defense officials have also yet to reach any conclusions about Tuesday’s launch.

We are assessing the specific nature of the recent launch event,” said a U.S. defense official who spoke on the condition of anonymity to discuss sensitive security matters. “We take any new capability seriously, and as we’ve said, we condemn any illicit missile launches, which are destabilizing to the region and to the international community.”

Despite the tactical differences, Chung praised the Biden administration’s thorough consultations and said frequent meetings with Blinken has meant the two allies remain in sync.

“We have been very frank with each other and we are completely on the same page,” Chung said.

Michelle Ye Hee Lee in Tokyo contributed to this report.