The July 20 images showed work at the Sohae Satellite Launching Station to dismantle a building used to assemble space-launch vehicles and a nearby rocket engine test stand used to develop liquid-fuel engines for ballistic missiles and space-launch vehicles, the 38 North thinktank said.
"Since these facilities are believed to have played an important role in the development of technologies for the North’s intercontinental ballistic missile program, these efforts represent a significant confidence-building measure on the part of North Korea," it said in a report.
Mr Trump told a news conference after his unprecedented 12 June summit with North Korean leader Kim Jong-un that Mr Kim had promised that a major missile engine testing site would be destroyed very soon.
Mr Trump did not identify the site, but a US official subsequently told Reuters that it was Sohae.
The 38 North report comes amid growing questions about North Korea's willingness to live up to the commitments Mr Kim made at the summit, particularly to work towards denuclearization.
US officials have repeatedly said North Korea has committed to giving up a nuclear weapons program that now threatens the United States, but Pyongyang has offered no details as to how it might go about this.
Jenny Town, managing editor of 38 North, which is based at Washington's Stimson Centre, said the work at Sohae could be an important move to keep negotiations going.
"This could (and that’s a big could) mean that North Korea is also willing to forgo satellite launches for the time being as well as nuclear and missile tests. This distinction has derailed diplomacy in the past," she said.
On Friday, senior US officials called on Mr Kim to act on his promise to give up his nuclear weapons and said the world, including China and Russia, must continue to enforce sanctions on Pyongyang until he does so.
On Monday, the US State Department issued an advisory together with the departments of Treasury and Homeland Security alerting businesses to North Korea's sanctions-evasion tactics.
It said they should "implement effective due diligence policies, procedures, and internal controls to ensure compliance with applicable legal requirements across their entire supply chains."
In a tweet early on Monday, Mr Trump rejected "Fake News" that he was angry because progress was not happening fast enough with North Korea.
"Wrong, very happy!" he said in the Tweet.
"A Rocket has not been launched by North Korea in 9 months. Likewise, no Nuclear Tests. Japan is happy, all of Asia is happy," he said.
A report in The Washington Post at the weekend said that in spite of positive assessments Trump has given on progress with North Korea, he has vented anger at aides over a lack of immediate progress.
Last week, Mr Trump said there was "no rush" and "no time limit" on denuclearisation negotiations.
US Director of National Intelligence Dan Coats said on Thursday it was technically possible for North Korea to eliminate its nuclear weapons program within a year, but added that it was not likely to happen.
The Independent
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