In the country’s first explanation for the incident last Thursday, foreign minister Paek Nam-sun said it had been a controlled detonation, according to reports by the BBC today. Paek’s claims were made to Bill Rammell, a British minister currently on a visit to North Korea.

Initial fears that the mystery explosion, which created a mushroom cloud over 3km in size, was the result of a nuclear test were quickly dismissed by both the US and South Korea.

Following a request for cooperation by Rammell, diplomats will now be allowed to visit the blast site in Yanggang province near North Korea’s border with China, reported a Reuters news update.