(CNN) North Korea is "livening up the mood" with regards to its talk on denuclearization, but doing very little beyond that, say experts who've long watched the isolated regime wrestle with its nuclear ambitions and international censure.

And further, they say, North Korean leader Kim Jong Un is positioning himself as an amenable leader open to negotiation as he readies for Friday's summit with South Korea and a forthcoming historic meeting with US President Donald Trump.

On Saturday Kim Jong Un asserted that his regime no longer needed to test its weapons capabilities and that it would be abandoning a test site in the north that had been the location of several nuclear tests.

"It's just propaganda, the statements have ambiguous meanings," said Chang-Hoon Shin, senior research fellow with the Korea Institute for Maritime Strategy. He said the test site at Punggye-ri in North Hamyong province would more likely be shut down because of the environmental impact sustained to the mountains there. When North Korea conducted its sixth nuclear test last September deep underground, the explosion created a magnitude 6.3 tremor

"We can say the Punggye-ri site was of no use anymore, so I think North Korea can make use of that situation by declaring they will shut down past sites, but it doesn't have any meaning," Shin told CNN.

"It can liven up the mood and make it favorable for the talks, but I don't think it's enough because it's not technically a move towards denuclearization at all."

If North Korea was really serious, Shin said, it would re-apply to the Non-Proliferation Treaty or accede to international norms under the Comprehensive Nuclear Test Ban Treaty . And there's been no indication it wants to do that.

No 'popping champagne bottles' yet

The announcement has done little more than solidify prospects the Trump-Kim summit will go ahead, said Catherine Dill, a research associate at the James Martin Center for Nonproliferation Studies at the Middlebury Institute of International Studies.

"I think that this certainly improves the odds for a Trump-Kim summit actually occurring, but it may complicate the longer term picture," Dill told CNN.

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"A careful reading of the announcement shows that North Korea is walking a fine line in exactly what they are conceding at this point: an end to testing does not automatically result in the verifiable dismantlement of the nuclear and missile programs. Verification of testing alone would be quite complex, and the verification of dismantlement would take years of careful negotiation and implementation," she said.

"I think that while this particular concession by North Korea appeals to Trump's vanity, it has improved dramatically the prospects for the summit," she added.

Abraham Denmark, director of the Asia Program at the Wilson Center, agreed.

"This is posturing, it's still not committing North Korea to anything. They actually committed to no testing before -- as recently as 2012 -- and that lasted about a week. So it's a good thing, but I'm not popping any champagne bottles at this point," he told CNN.

In 2012, the North Korean regime agreed to halt its nuclear testing in exchange for food aid from the United States, the so-called Leap Day agreement. But the deal fell apart after North Korea launched a rocket into orbit several months after the deal was signed. The North Koreans said the rocket was sending a satellite into orbit, but the US, South Korea and Japan claimed that was a cover for a long-range ballistic missile test.

Lack of concrete measures

If North Korea is so confident in its weapons capacity and wants to join the nuclear club, then it should abide by conventions adhered to by other nuclear states, Shin notes.

"In order not to be deceived by North Korea again, concrete measures and gestures must be shown by Pyongyang," he told CNN. "Talking of denuclearization gives a certain illusion, but there must be certain measures like returning to the IAEA [International Atomic Energy Agency]. I argue that returning to those organizations are the minimum standard for verifying their real intention or will of denuclearizing."

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North Korea pulled out of the nuclear non-proliferation treaty in January 2003, declaring at the time that it pledged to limit its nuclear activities to "peaceful purposes." It had announced in 1993 that it would withdraw from the treaty then, but suspended the decision to enter into talks with the US.

By choosing to focus on direct talks with the US, Shin says North Korea is bypassing the scrutiny and verification process it would have to accept under UN auspices.

"If you look at the relevant UN Security Council resolutions , the resolutions always ask North Korea to return to the IAEA and the NPT, so North Korea knows very well, it's trying to avoid such situations, it wants to discuss denuclearization directly with the US rather than in the context of international norms," Shin said.

"If North Korea can lift US sanctions first, then the UN sanctions aren't as significant."

A deal for a deal's sake

The announcement follows diplomatic outreach including a visit by Kim to Beijing, his first foreign visit as leader, to meet with Chinese President Xi Jinping . In a comment Saturday, Chinese foreign ministry spokesman Lu Kang welcomed the latest developments. "Achieving denuclearization and sustainable peace in the region is in the interest of people on the peninsula and in the region, and meet the shared expectation of the international community," said Lu.

"We hope all relevant parties will move in the same direction and take concrete actions to work toward sustainable peace and common development in the region. China will continue to play a positive role to this end."

Meanwhile, President Trump responded positively to the news out of Pyongyang, tweeting about it twice on Friday night . The news that North Korea was suspending its tests and closing down a site, he said, was "very good news for North Korea and the World - big progress! Look forward to our Summit."

But at least one American ally in the region was circumspect.

"The only thing that is important is whether or not it will lead to the completely verified and irreversible abolition of nuclear and missiles," Japanese Prime Minister Shinzo Abe told reporters. "We would like to keep a close eye on it."

His defense minister was even more direct, calling the announcement "insufficient."

Speaking in Washington, DC, Itsunori Onodera told reporters that the move was "not satisfactory" for Japan "as the disposal of middle and short-range missile and of nuclear weapons was not mentioned."

He added that Japan will continue its policy of "maximum pressure" until "North Korea gives up WMDs [weapons of mass destruction] and nuclear missiles completely."

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Japan's fear is that, in a bid to get a win, Trump will be satisfied with a commitment from North Korea to abandon nuclear weapons and intercontinental ballistic missiles, but not give up its short and medium-range weapons that are able to target Japan.

"So far, White House officials have been saying that the US is not going to give anything until North Korea completely denuclearizes, it's setting a very hard line on negotiations," said Denmark.

"But as we've seen in the past the President doesn't necessarily follow through on the advice of his people and so it's impossible to know what's going to happen when he gets in a room and sits down with Kim. Even if they come to an agreement, the president has demonstrated a penchant in his life of pulling out of agreements so sticking to an agreement is going to be very difficult," he said.