TOKYO — North Korean leader Kim Jong Un has declared that he will suspend nuclear and missile tests starting Saturday and that he will shut down the site where the previous six nuclear tests were conducted.

The surprising announcement comes just six days before Kim is set to meet South Korean President Moon Jae-in, a precursor to a historic summit between Kim and President Trump. The U.S. president is set to meet Kim at the end of May or beginning of June, although a location has not yet been set.

Both Moon and Trump have been saying that North Korea is now willing to “denuclearize,” a term that means different things to the two sides.

“North Korea has agreed to suspend all Nuclear Tests and close up a major test site,” Trump tweetedshortly after the announcement from Pyongyang. “This is very good news for North Korea and the World — big progress! Look forward to our Summit.”

But Kim’s statement on Saturday made no mention of North Korea giving up its program. It simply signaled a freeze, apparently because the leader is satisfied with the rapid progress the country made last year, developing what it said was a “super large heavy warhead” and a missile capable of carrying it to the U.S. mainland.

North Korea has “verified the completion of nuclear weapons,” Kim reportedly said during a meeting of the central committee of the ruling Workers’ Party of Korea, convened Friday to discuss policy issues related to “a new stage” in a “historic” period.

As such, it “will stop nuclear tests and launches of intercontinental ballistic missiles” effective immediately, he said.

“We no longer need any nuclear test or test launches of intermediate and intercontinental range ballistic missiles, and because of this the northern nuclear test site has finished its mission,” the official Korean Central News Agency quoted Kim as saying.

There has been considerable skepticism among North Korea experts that Kim, having poured so much money and effort into the program, not to mention his personal prestige, would give it up so readily.

Many pointed out that Kim’s statement does not in any way suggest that he’s about to do so.

“There is nothing in North Korea’s statement that signals a willingness to give up their nukes,” said Benjamin Silberstein, a North Korea researcher at the University of Pennsylvania.

Why does North Korea hate the U.S.? Look to the Korean War. Anna Fifield, Jason Aldag/The Washington Post)

“On the contrary, the tone of the message is one of confidence and strength,” he said.

[No ‘lunatics’ or ‘war maniacs’: North Korea dials down the anti-U.S. rhetoric ]

Still, the step is part of a broader and rapidly developing effort to use diplomacy to resolve the standoff on the Korean Peninsula, following months of threats at the end of last year that stoked fears of a military conflict.

Next Friday, Kim will cross the Military Demarcation Line that has divided the peninsula since the end of the Korean War, becoming the first North Korean leader to do so since then. He will step into “Peace House” on the southern side of the line to meet Moon, with their encounter being broadcast live.

Moon signaled this week that everything was on the table at the meeting.

“North Korea is expressing its intention for complete denuclearization,” Moon said Thursday. “And it is not making demands that the U.S. cannot accept, such as the withdrawal of the U.S. forces in Korea.”

The U.S. military has 28,000 troops stationed in South Korea, with backups in Japan and on Guam — the legacy of the standoff that has ensued since the Korean War ended in an armistice in 1953.

Trump also this week voiced optimism about his summit with Kim, although he said he would walk away from the talks if they were not looking constructive.

“I think we’re going to be successful,” Trump said shortly after it was revealed that his CIA director, Mike Pompeo, met Kim in Pyongyang over the Easter weekend for talks about the summit. “But for any reason if I think we’re not, we end,” the president said.

[Under pressure to show results on North Korea, Trump can’t stop raising the bar for success ]

As the presidents of South Korea and the United States prepare for summits with the previously reclusive Kim, there has been much conjecture about what exactly the North Korean leader is prepared to discuss.

North Korea had said very little about all this — and that had plenty of analysts worried that expectations for this summit are too high.

The fact that the North has now signaled it is prepared to at least freeze its program is extremely significant, said Daryl G. Kimball, executive director of the Arms Control Association in Washington.

“North Korea’s pledge to close down its nuclear weapons testing site is a very significant pledge toward denuclearization,” Kimball said. “The U.S. and others should solidify this by securing North Korean signature and ratification of the 1996 Comprehensive Nuclear Test Ban Treaty, along with a confidence-building visit by the Comprehensive Test Ban [Treaty] Organization.”

Others point out that North Korea has been sending signals through what it has not been saying. It’s not talking about the U.S. strike on Syria, about the U.S. military conducting drills in South Korea, or about the “heinous” and “hostile” United States.

It hasn’t even commented on the return of national security adviser John Bolton, a man the regime once derided as “human scum and a bloodsucker.”

This is a sharp change from its usual tirade of vitriol against the United States, especially at this time of year, when the U.S. and South Korean militaries are practicing war drills on the southern half of the peninsula.

It also hasn’t been using one of its favorite phrases, about being a “strong nuclear power,” since March 10 — the day after Trump agreed to meet with Kim. Previously, the phrase had appeared in the Rodong Sinmun, the mouthpiece of the Workers’ Party, on a daily basis.

“That’s not a coincidence,” said Peter Ward, a North Korea researcher at Seoul National University. “I think North Korea is on a serious drive for peace right now.”

[North Korea’s definition of ‘denuclearization’ is very different from Trump’s ]

But others were more circumspect, noting that Saturday’s announcement fits with North Korea’s previous declarations that it had “completed” its nuclear and missile programs.

“This echoes what Kim Jong Un has already said about its nuclear program. Kim Jong Un is satisfied,” said Melissa Hanham, a researcher at the James Martin Center for Nonproliferation Studies in Monterey, Calif.

“This means North Korea is also satisfied with fewer tests than many other states that possess nuclear weapons,” she said.

Last year was an exceptionally busy one for North Korea’s nuclear and missile specialists. In September, the country detonated a huge nuclear device that it said was a hydrogen bomb.

This claim, experts said, was supported by the size of the blast, which caused a 6.3-magnitude earthquake in North Korea’s northeast, an area not known for natural seismic activity.

Mount Mantap, the 7,200-foot-high peak under which North Korea has detonated all its nuclear bombs, visibly shifted during that last nuclear test, leading some analysts to wonder if it was suffering from “tired mountain syndrome” and was at risk of collapsing.

If that were true, closing the site would be something North Korea would do anyway, although perhaps without announcing it at such a fortuitous time, if at all.

Then, after launching several intercontinental ballistic missiles in the middle of the year, the North fired an ICBM that it said put the entire U.S. mainland within reach and could carry a “super large heavy warhead.”

With that test, North Korea declared that its “rocket development process has been completed.”

(The Washington Post)