TOKYO — North Korean leader Kim Jong Un said he is ready to meet President Trump at any time to discuss the denuclearization of the Korean Peninsula but warned he might have to seek “new ways” if the United States maintains sanctions and demands unilateral concessions.

In a closely watched, nationally televised annual New Year’s Day speech, Kim said for the first time that his country had already stopped producing nuclear weapons, adding that progress on denuclearization could accelerate if the United States also makes concessions.

But he balanced a willingness to talk with a reminder that North Korea has its own demands if denuclearization is to happen. He also warned that the United States should not misjudge North Korea’s “patience.”

Kim called his June summit meeting with Trump “instructive” and said they had shared “constructive opinions” on mutual concerns and “speedy solutions to the tangled issues” they faced.

“I am ready to sit face to face with the U.S. president again any time in the future and will strive to produce an outcome welcomed by the international community,” he said.

“However, if the U.S. does not keep the promises it made in front of the world, misjudges the patience of our people, forces a unilateral demand on us, and firmly continues with sanctions and pressures on our republic, we might be compelled to explore new ways to protect our autonomy and interests, and establish peace and stability on the Korean Peninsula,” he said.

On the other hand, Kim reminded his audience that he and Trump had agreed to proceed toward the “complete denuclearization” of the peninsula, and he said that remained the “unchangeable stance” of the ruling Workers’ Party of Korea and the government of the Democratic People’s Republic of Korea (DPRK), as well as his own “firm will.”

“We have announced that we will not produce, test nor proliferate any more nuclear weapons, and have taken practical measures accordingly,” he said. “If the United States responds to our preemptive and autonomous efforts with credible measures and corresponding actions, the relationship between the two countries will accelerate for the better.”

In a tweet later Tuesday, Trump referenced Kim’s speech and said he looked forward to “meeting with Chairman Kim who realizes so well that North Korea possesses great economic potential!”

Robert Carlin, a visiting scholar at Stanford University, said the last time North Korea made such a commitment not to make nuclear weapons was a 1992 joint declaration with South Korea. 

“What we have is the DPRK leader, on the record, telling us the North Koreans will not, have not produced any more nuclear weapons,” he said. “I wouldn’t dismiss it. I don’t know what it means exactly, but Kim said it, and we should take it seriously and probe it.”

Carlin, who was involved in North Korea talks from 1992 to 2000 and is a nonresident fellow at the Stimson Center, also noted that Kim’s warning to the United States used relatively soft words such as “might” and “explore” — while he attached his own “firm will” to the commitment to denuclearize.

“Now what Kim has done is laid out in a very positive way for his domestic audience how forward-leaning he is in terms of engaging with the U.S., and in fact, he makes it very personal,” he said. “He did that for a reason — because, I believe, he thinks this is going to move ahead.”

Whether North Korea is not producing nuclear weapons remains very doubtful, but at least Kim is pledging to act with restraint for now, said Andrei Lankov, a professor at Kookmin University in Seoul. But Lankov pointed out that Kim had again talked of the denuclearization of the Korean Peninsula rather than of North Korea, which are two different things.

“That’s not a new formula. It’s more than 25 years old,” he said, “and it essentially implies the withdrawal of U.S. forces from Korea and maybe from adjacent areas, as well.”

Lankov says that Kim is offering a reduction in his nuclear arsenal and detente in return for sanctions relief and diplomatic gains but not total nuclear disarmament. 

That is a compromise that appeals to many people who say it will reduce regional tensions considerably — but not to many senior figures in Washington, who say it would set a dangerous precedent by recognizing North Korea as a de facto nuclear weapons state.

Kim delivered the speech in a more relaxed setting than in previous years, sitting in a plush leather armchair in a book-lined study, with large paintings of his father and grandfather alongside flags of North Korea and the Workers’ Party on the wall behind him.

Overall, it felt like a North Korean imitation of the British aristocracy of the 19th century, mixed with a touch of President Franklin D. Roosevelt’s “fireside chats” of the 1930s and 1940s, Lankov said — even if the canned mass applause at the end of the speech was more typical of Pyongyang’s heavy propaganda touch.

Portraying a more approachable image than his father, Kim was seen sauntering to the study along a corridor, his Western-style jacket unbuttoned, followed by his younger sister, Kim Yo Jong, who is emerging as a key figure in his entourage.

The speech, primarily aimed at a domestic audience, was mostly concentrated on the economy and stressed the need for self-reliance, technological progress and scientific research while upholding socialist values. He urged North Korea to improve its infrastructure, address power shortages by raising electricity production and boost the munitions industry to bring the country’s defense capabilities “up to the level of developed countries.”

He spoke warmly of his three meetings with South Korean President Moon Jae-in in 2018 and the rapprochement between the two nations but said that progress should be consolidated by ending joint military exercises with the United States. He also called for a halt to the deployment of “strategic assets” on the Korean Peninsula, an apparent reference to U.S. bombers and submarines capable of carrying nuclear weapons.

Kim said he wanted to restart a joint economic zone in Kaesong and a joint tourism project at Mount Kumgang in the North “without preconditions.” However, neither step will be possible unless sanctions are lifted.

South Korea’s presidential Blue House praised the speech, saying Kim’s commitment to closer inter-Korean ties would “make a positive contribution to the prospect of Korean Peninsula issues being solved smoothly in the New Year.”

Kim also sent a letter to Moon on Sunday, expressing his willingness to meet the South Korean leader “often” in the coming year to move their peace process and denuclearization talks forward, according to the Blue House. He also sent a “conciliatory message” to Trump, according to Bloomberg News.

A year ago, the 2018 New Year’s Day address came at a time of much greater tension, but Kim used that opportunity to balance tough talk with a rare olive branch to South Korea.

In that speech, Kim said he had a “nuclear button” on his desk with weapons capable of reaching the United States, but he also opened a path to dialogue with Seoul and expressed willingness to send a delegation to the Winter Olympics in South Korea. 

In this year’s address, Kim reminded viewers that athletes from the two Koreas had marched together under a joint Korean flag at the Opening Ceremonies of those Games.