Satellite imagery of a North Korean nuclear test site reportedly reveals hectic activity, sparking fears of a potential missile launch or nuclear test. Images from a commercial satellite of the Punggye-ri nuclear test site in North Korea purportedly show four or five vehicles or trailers present at the entrance of the site where North Korea's previous four nuclear tests took place.

The activity may indicate that North Korea is gearing up for its sixth nuclear test. Satellite images also indicate that some construction material, presumably sand and aggregate, remains undisturbed at the site, according to a report by US think tank 38 North.

The report stated: "That material, if it is sand and aggregate, when mixed with concrete, may be intended to 'stem,' that is to plug segments of the tunnel to prevent a nuclear explosion from escaping into the atmosphere."

Satellite images also reportedly show that apart from a few mining carts and two trucks at the West Portal, there's little to no activity at the nuclear site. According to 38 North, this lack of activity may indicate that either "Pyongyang is in the final stages of test preparation or that the site is in a standard operating mode."

On Friday (24 March), South Korean officials warned that Pyongyang appeared to be in the last stages of preparing for yet another nuclear test and could carry out detonations within hours of an order issued by leader Kim Jong-un.

Numerous reports surfaced last week about North Korea preparing for yet another potential missile or nuclear test, amid rising tensions with its neighbours and the West.

It remains unclear whether the reported presence of the vehicles at the Punggye-ri nuclear site is indicative of Pyongyang's willingness to conduct yet another nuclear test.