TOKYO — North Korea said Friday it was "premature" to declare a formal end to the Korean War, after a reference to renewed efforts by South Korean President Moon Jae-in to put the discussion back on the table amid stalled nuclear negotiations with Pyongyang.

Kim Yo Jong, the powerful sister of the North Korean leader, said in a statement Friday that the declaration was "an interesting and an admirable idea," but that it was not the right time.

Through two statements released via state media Friday, top North Korean officials said that declaring a formal end to the war would not guarantee an end to "hostile policies" toward North Korea.

Sustained fighting in the Korean War ended with an armistice agreement in 1953, but the two Koreas remain technically at war.

In his speech at the United Nations General Assembly meeting this week in New York, Moon again called for an end-of-war declaration, which he views as a way to move forward in denuclearization talks. Moon proposed that the two Koreas, along with the United States and China, come together for the declaration.

After Moon’s speech, Pentagon spokesman John Kirby said the United States is open to “discussing the possibility” of an end-of-war declaration, in an effort to achieve “the complete denuclearization of the peninsula.”

North Korea has previously called for a formal end to the war, including during 2018 negotiations with South Korea and the United States.

North Korean Vice Foreign Minister Ri Thae Song first issued a statement that analysts say was directed at the United States, calling out recent joint U.S.-South Korean military drills and the new submarine deal between the United States, Australia and Britain.

“Nothing will change as long as the political circumstances around the DPRK remains unchanged and the U.S. hostile policy is not shifted, although the termination of the war is declared hundreds of times,” Ri said in the statement, referring to the formal name of his country, the Democratic People’s Republic of Korea.

Ri said declaring the end of the war “is not a ‘present’ and it can become a mere scrap of paper in a moment upon changes in situations,” and called U.S. policy a “double standard.”

In her own statement, Kim then struck a more forward-leaning tone directed at Moon, saying that North Korea would “have willingness to keep our close contacts with the South again and have constructive discussions” to improve inter-Korean relations if the South did not provoke or make “far-fetched assertions.”

Kim said Pyongyang had certain preconditions of Seoul, adding that “respect for each other should be maintained and prejudiced viewpoint, inveterate hostile policy and unequal double standards must be removed first.”

South Korea has typically raised the end-of-war declaration as a tool to generate momentum on talks with North Korea, said former Pentagon official Frank Aum, a senior expert on Northeast Asia at the U.S. Institute of Peace.

North Korea has agreed to such a declaration in theory but has wanted to see tangible guarantees, he said.

“They’re recognizing that, ‘Hey, it doesn’t provide any binding benefits, obligations. What’s the point of it right now?’ ” Aum said. “It doesn’t really address what North Korea really wants, which is sanctions relief or other tangible guarantees.”

Jenny Town, director of the North Korea monitoring program 38 North, said the message from Ri appeared to be: “This isn’t 2018. . . . Times have changed so much.”

“They didn’t say it’s off the table. They said it’s not the right time, and they still put it in the condition of U.S. hostile policy,” Town said. “It doesn’t mean that there’s no chance for negotiation, but it does mean that it won’t be easy, and the price of everything has gone up.”