0829 GMT November 30, 2020
Leader Kim Jong-un convened an emergency politburo meeting on Saturday to implement a "maximum emergency system and issue a top-class alert" to contain the virus, the official Korean Central News Agency said, according to AFP.
If confirmed, it would be the first officially recognized case of COVID-19 in North Korea.
Pyongyang previously insisted that not a single case of the coronavirus had been seen in the North despite the pandemic sweeping the globe, and the country's borders remain closed.
The patient was found in Kaesong city, which borders South Korea, and "was put under strict quarantine", as would any close contacts, KCNA said.
It was a "dangerous situation... that may lead to a deadly and destructive disaster", the agency added.
Kim was quoted as saying "the vicious virus could be said to have entered the country", and officials on Friday took the "preemptive measure of totally blocking Kaesong ".
North Korea closed its borders in late January as the virus spread in neighboring China and imposed tough restrictions that put thousands of people into isolation.
Experts believe the contagion is likely to have already entered North Korea from China, where the new disease emerged late last year.
China and North Korea share a 1,400-kilometer border that is especially porous during the winter, when frozen rivers allow people to cross more easily in and out of the two countries.
Dozens of North Koreans cross the border to smuggle black market goods every day and analysts have said they may have carried the virus into the country before the frontier was closed.
Earlier this month Kim warned against any "hasty" relaxation of anti-coronavirus measures, indicating the North would keep its borders closed for the foreseeable future.
Global infection rate
At least 645,000 people around the world have succumbed to the respiratory disease, with the United States the worst-hit country by far as the number of people infected worldwide passed 16 million.
The pandemic's spread is still accelerating, with more than five million cases declared since July – a third of the total number of cases since the catastrophe began.
Even in recent days there has been an alarming uptick in infections, including in places that had appeared to have controlled their outbreaks.
Around a quarter of the world's 16 million confirmed COVID-19 cases are in the United States, which recorded more than 68,000 new infections in the past 24 hours.
In Latin America and the Caribbean, which also count for a quarter of total cases, governments are not planning a return to normality any time soon.
Meanwhile Europe has reported around three million infections – despite being largely open for summer holidays within the continent.
In India, for instance, millions of migrant workers who fled cities when COVID-19 hit say they are too scared to return.
Asia's third largest economy has reported more than 1.3 million virus cases and is the third worst hit country behind the US and Brazil.