North Korea reported Thursday its very first case of COVID-19 on its territory since the start of the pandemic and ordered nationwide “containment” measures.

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Here's what we know:

North Korean state media reported that "people with fever" in the capital Pyongyang have tested positive for COVID-19, without specifying the number.

The virus may have already spread across the country, analysts say, including major events in April in Pyongyang, including a military parade in which neither participants nor spectators wore masks.

"People from all over the country attended these events and were able to bring the virus back," Park Won-gon, a professor at Ewha University in Seoul, told AFP.

The fact that North Korean leader Kim Jong Un chaired an urgently called Politburo meeting and that its content was immediately published by the official media, which usually wait until the next day, testifies to the gravity of the situation.

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

It immediately expelled all foreign nationals - including diplomats and international aid workers - and banned all arrivals from abroad. The country has been totally reclusive for more than two years.

The regime hailed the strategy's success, but experts said due to the outbreak in neighboring countries, it was inevitable that COVID-19 cases would eventually appear in North Korea.

It could have been imported by someone who crossed the border illegally from China or via an animal, such as a bird or a wild boar, experts said.

North Korea and China suspended rail links in April, Pyongyang worried about a risk of contamination, but shipments of goods by sea continued.

"The North Korean sailors may have been infected by other crews," said the specialized site NK News, based in Seoul.

Due to notoriously poor health infrastructure, the absence of vaccines and antiviral treatments, the possibilities are limited.

Kim Jong Un has ordered nationwide "lockdown" measures, according to the KCNA news agency. Details on what these restrictions cover were not disclosed.

"North Korea will probably do the same as China," said Go Myong-hyun, a researcher at the Seoul-based Asan Institute of Policy Studies.

But unlike China, no inhabitant is vaccinated and the country lacks the means to massively screen the population. It also has few means to treat the most serious cases.

The country could therefore record a "large number of deaths", says Lim Eul-chul, a professor at Kyungnam University in Changwon.

Pyongyang's announcement comes days after the inauguration of South Korea's new president and a week before US President Joe Biden's expected visit to Seoul.

Pyongyang has already rejected offers of assistance and vaccination made in particular by the WHO and its main ally, China.

Mr. Kim is unlikely to ask for help now.

This would amount to "acknowledging the failure of the anti-COVID system put in place so far and will cause considerable harm to Kim Jong Un's mode of governance", according to Mr. Lim.

South Korea's new government has, however, allocated a budget to send COVID vaccines to the North, said Kwon Young-se, a candidate for unification minister.

Despite a dire economic situation and chronic food shortages, North Korea spends a significant portion of its GDP on its banned weapons programs.

Mr Kim has repeatedly pledged to resolve 'food, clothing and housing issues, but has continued firing missiles - more than a dozen this year - and there are signs he may resume his nuclear tests.

In the event of an epidemic, "the population could be less interested in these tests (nuclear or missiles) because of the more urgent threat posed by the coronavirus rather than a foreign army", thinks Leif-Eric Easley, professor at Ewha University.

However, for Mr. Yang if public fears of an epidemic spread, Kim Jong Un could carry out a trial "to deflect this fear".