North Korea is continuing to carry out rapid improvements to its nuclear research facility, reported 38 North, a website monitoring Pyongyang.

North Korea’s leader Kim Jong-un had promised to work towards denuclearising the Korean peninsula during his meeting with United States President Donald Trump in Singapore on June 12. Trump and Kim had signed a joint statement in which the US agreed to establish official diplomatic relations.

According to 38 North, commercial satellite imagery showed that operations were continuing at North Korea’s main nuclear site, Yongbyon Nuclear Scientific Research Centre, and that improvements to infrastructure were moving at a rapid pace.

Last week, Trump renewed sanctions against North Korea for a year, claiming that the country still poses an “extraordinary threat”. Trump’s statement came after he had claimed during the summit that North Korea was “already destroying a major missile site”.

It noted “continued operations” at the North’s uranium enrichment plant and new installations at the site – including an engineering office and a driveway to a building housing a nuclear reactor.

“Continued work at the Yongbyon facility should not be seen as having any relationship to North Korea’s pledge to denuclearise,” the report said. “The North’s nuclear cadre can be expected to proceed with business as usual until specific orders are issued from Pyongyang.”

On May 24, North Korea said it had dismantled its nuclear bomb test site in Punggye-ri, as a goodwill gesture before the meeting with Trump. US Secretary of State Mike Pompeo has been pushing for more talks to flesh out details over denuclearisation but no date has been set for when they would take place.