Based on satellite images, US-based monitoring group 38 North said that they have witnessed a visible change in the Sohae satellite launching station, a key North Korean rocket launching site situated in the country's north-west.

Following the development, US President Donald Trump tweeted: "A Rocket has not been launched by North Korea in 9 months. Likewise, no Nuclear Tests. Japan is happy, all of Asia is happy. But the Fake News is saying, without ever asking me (always anonymous sources), that I am angry because it is not going fast enough. Wrong, very happy!"

Earlier this month, Trump had said that he will not be rushing North Korean leader Kim Jong-un to denuclearise the Korean Peninsula.

He had told reporters: "We have no time limit. We have no speed limit. Discussions are ongoing, and they're going very, very well." 

However, despite all the positive reports regarding North Korea's nuclear tests (or the lack of it), reports have emerged that the country is still secretly upgrading its nuclear enrichment sites.

A report earlier this month stated that Pyongyang is bolstering its official nuclear enrichment site at Yongbyon, simultaneously, it's investing in another two secret sites.

The reports, still unverified, have been deemed accurate by watchdogs.

Senior Editor of The Diplomat, Ankit Panda has tweeted: "For years, nonproliferation experts & #NorthKorea watchers have suspected the existence of covert uranium enrichment sites in the country. Now, for the first time, we've found one. Introducing the Kangson enrichment site: https://thediplomat.com/2018/07/exclusive-revealing-kangson-north-koreas-first-covert-uranium-enrichment-site/ … (cc @ArmsControlWonk)"

However, Vipin Narang, MIT professor for political science and specialist on nuclear proliferation, was quoted by the BBC as saying that none of the actions performed by Pyongyang contradicts the agreement they signed in Singapore, where the historic meeting between US President Donald Trump and North Korean leader Kim Jong-un too place last month.

"None of that activity is in violation of any agreements made at the Singapore summit between US President Donald Trump and North Korean leader Kim Jong-un," he says, adding, "This was never going to be unilateral and immediate. So Kim Jong-un is free to continue operating the existing sites."

Image: twitter.com/realDonaldTrump