North Korean authorities have imposed a lockdown on the border city of Kaesong after discovering the country’s first suspected case of the novel coronavirus, according to the state media on Sunday.

Leader Kim Jong Un convened an emergency politburo meeting to implement a “maximum emergency system and issue a top-class alert” to contain the virus, official news agency KCNA said.

If confirmed, it would be the first officially recognised COVID-19 case in the North where medical infrastructure is seen as woefully inadequate for dealing with any epidemic.

KCNA said a defector who had left for the South three years ago returned on July 19 after “illegally crossing” the heavily fortified border dividing the countries.

But there have been no reports in the South of anyone leaving through what is one of the world’s most secure borders, replete with minefields and guard posts.

The patient was found in Kaesong City, which borders the South, and “was put under strict quarantine”, as would anybody who had come in close contact, state media said.

It was a “dangerous situation… that may lead to a deadly and destructive disaster”, the media outlet 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 City”.

South Korea is currently recording around 40 to 60 cases a day.

Earlier this month, Kim Jong-un had called for “maximum alert” against the coronavirus pandemic, during a politburo meeting of the ruling Workers’ Party, and warned that premature easing of anti-virus measures will lead to “unimaginable and irretrievable crisis”.

Kim also made “sharp criticism of inattention, onlooking and chronic attitude getting prevalent among officials, and violation of the rules of the emergency anti-epidemic work as this work takes on a protracted character”.

North Korea earlier had claimed to have no coronavirus infections, but it has taken relatively swift counter measures since January, such as closing its border and toughening quarantine criteria.

(With inputs from agency)