SEOUL (AFP) - It was supposed to be a triumphant celebration of North Korea's martial prowess, but a huge military parade to celebrate the army's founding could inadvertently have spread Covid-19 nationwide, experts say.

North Korea on Friday (May 13) confirmed its first ever coronavirus death, a day after the reclusive regime admitted to Omicron cases, saying tens of thousands of people were isolating after a fever "explosively spread nationwide from late April".

North Korea staged a massive military parade in Pyongyang on April 25 to celebrate the founding anniversary of the army.

Footage of the event on state television showed thousands of people - unmasked and not socially distanced - packed into Pyongyang's Kim Il Sung square to watch ranks of soldiers goose-step past, and applaud as huge missiles were driven by.

The current Covid-19 outbreak is "closely linked to the April 25 parade", Hong Min, a researcher at the Seoul-based Korea Institute for National Unification told AFP.

"More than 20,000 people were preparing for the parade for two months prior to the event and stayed on in the capital for photo ops with Kim Jong Un," he said.

Kim's regime only appears to have "realised the gravity" of the situation belatedly and carried out Covid-19 testing after parade participants returned to their districts.

"Holding a military parade attended by a large crowd, when Omicron was raging in neighbouring China, shows Pyongyang was overconfident in their capabilities to fight and prevent the virus," said Cheong Seong-chang of the Sejong Institute.

Not their first parade

North Korea was one of the first countries to close its borders in January 2020 after the virus first emerged in neighbouring China.

Its policy of strict isolation initially appeared to keep Covid-19 at bay, and the country reported no cases for two years - although some experts question this claim.

Pyongyang even staged a night-time military parade in September 2021 with no reported consequences, although photographs of that event show participants wearing masks.

But over time, it seems North Korea may have relaxed its guard domestically, with state media reporting on anti-epidemic work more sporadically, analysts said.

At the time of the 2021 parade, the movement of people and goods to and from China "was largely restricted", Yang Moo-jin, a professor at the University of North Korean Studies told AFP.

But earlier this year, North Korea briefly eased its near-total lockdown of cross border trade with China - likely the root cause of the current Omicron outbreak, he said.

"The virus may have entered North Korea via three different routes: railroads, shipping and smuggling," he said.

"The point is it came from China."