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Kim saluted as ranks of goose-stepping soldiers followed by tanks and other military hardware paraded in Pyongyang for a show of strength with tensions mounting over his nuclear ambitions. / AFP PHOTO / ED JONES        (Photo credit should read ED JONES/AFP/Getty Images)
ED JONES/AFP/Getty Images
North Korean leader Kim Jong-Un waves from a balcony of the Grand People's Study house following a military parade marking the 105th anniversary of the birth of late North Korean leader Kim Il-Sung, in Pyongyang on April 15, 2017. Kim saluted as ranks of goose-stepping soldiers followed by tanks and other military hardware paraded in Pyongyang for a show of strength with tensions mounting over his nuclear ambitions. / AFP PHOTO / ED JONES (Photo credit should read ED JONES/AFP/Getty Images)
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Britain's Prince Philip, Duke of Edinburgh, in his role as Captain General, Royal Marines, attends a Parade to mark the finale of the 1664 Global Challenge on the Buckingham Palace Forecourt in central London on August 2, 2017. After a lifetime of public service by the side of his wife Queen Elizabeth II, Prince Philip finally retires on August 2, 2017,at the age of 96. The Duke of Edinburgh attended a parade of Royal Marines at Buckingham Palace, the last of 22,219 solo public engagements since she ascended to the throne in 1952. / AFP PHOTO / POOL / HANNAH MCKAY (Photo credit should read HANNAH MCKAY/AFP/Getty Images)
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(CNN) —  

Satellite images appear to show that North Korea has begun rebuilding a portion of a facility previously used to test long-range missile engines, analysts said Tuesday, raising potential questions about the future of US-North Korea negotiations.

The Center for Strategic Studies’ Beyond Parallel project and 38 North, both respected North Korea monitoring websites, each said it had observed activity at the Tongchang-ri satellite launch facility, which has been dormant since about August of last year.

A satellite image of Tongchang-ri.
CSIS/Beyond Parallel/DigitalGlobe 2019
A satellite image of Tongchang-ri.

Tongchang-ri is one of the few known missile component development facilities inside North Korea.

38 North found that efforts to rebuild the site’s launch pad and missile engine test stand began sometime between February 16 and March 2, meaning work began either in the days before, during, or immediately after North Korean leader Kim Jong Un and US President Donald Trump abruptly ended their second summit in Hanoi on February 28 without signing a deal.

Satellite launches use similar technology as ballistic missiles, and experts have long cautioned that North Korea’s attempts to shoot satellites into space could help them develop viable long-range ballistic missiles.

Beyond Parallel reported there has been “activity” at a vertical engine test pad and a launch pad’s rail-mounted rocket transfer structure. It concluded that the activity was “deliberate and purposeful.”

The CIA declined to comment on the photographs.

South Korean lawmaker Lee Hye-hoon told CNN Wednesday that the country’s National Intelligence Service (NIS) revealed in a briefing that there has been restoration activity at Tongchang-ri.

Speaking Wednesday, Trump said it was “too early to see” whether Kim had restarted the country’s missile testing program but added that he would be “very disappointed” if that turned out to be the case.

Asked whether Kim broke his promise, Trump told reporters: “We’re gonna see. It’s too early to see. But we have to solve a problem. We have a really nasty problem. We have to solve a problem.”

Tongchang-ri activity

Though the satellite images provide useful information, analysts and experts caution against reading too much into them without sufficient intelligence to complement.

“If North Korea does something they want us to know, they would say it. They haven’t said anything,” said Joseph Yun, the State Department’s former special representative for North Korea policy.

“We don’t know enough to say one way or the other. My own guess is it’s too early to think that this is a response to happen in Hanoi,” Yun said.

Joel Wit, a former State Department diplomat and founder of 38 North, said on Twitter that the movement at Tongchang-ri did not provide any evidence that North Korea was preparing to test an intercontinental ballistic missile.

But the activity is surprising. After Trump and Kim’s first summit in Singapore, the US President appeared to tout reports that North Korea had begun dismantling the Sohae Satellite Launching Station, another name for Tongchang-ri.

Dave Schmerler, a senior research associate at the Center for Nonproliferation Studies specializing in satellite imagery analysis, said that the more notable development is the work being done to the engine test stand, where Pyongyang could theoretically improve the engines on its nuclear-capable missiles.

North Korea has already successfully tested two types of ICBMs on mobile launchers, so it doesn’t necessarily need the launch pad to test-fire long-range missiles.

It’s also possible that the activity at the facility is a chess move in North Korea’s negotiating strategy, Schmerler said, to ratchet up pressure on Washington.

Trump and Pompeo have touted as progress the fact that North Korea has not conducted any missile or nuclear tests in more than a year.

“The site itself, in the macro-sense, is very transparent. And the North Koreans know we are always watching,” he said.

“When they do something at Sohae, they know that this could very easily be in the public conversation for domestic American politics.”

It’s unclear if the recent developments will affect how the White House moves forward with North Korea.