North Korean leader Kim Jong Un placed the city of Kaesong near the border with South Korea under total lockdown over coronavirus concerns and declared a state of emergency to contain a potential outbreak, the North's state media reported Sunday.

The step was taken Friday afternoon after a person was found with suspected COVID-19 symptoms in the city, the Korean Central News Agency said. It said the person is a runaway who had fled to South Korea years ago before illegally crossing the border into the North early last week.

If that person is officially declared a virus patient, he or she would be the North’s first confirmed coronavirus case. North Korea has steadfastly said it has no single virus case on its territory, a claim questioned by outside experts.

During an emergency Politburo meeting Saturday, Kim also declared a state of emergency in the Kaesong area, KCNA said. It quoted Kim as saying that there was “a critical situation in which the vicious virus could be said to have entered the country,.”

Kim said he took “the preemptive measure of totally blocking Kaesong City and isolating each district and region from the other within July 24 afternoon just after receiving the report on it,” according to KCNA.

Describing its anti-virus efforts as a “matter of national existence," North Korea earlier this year shut down nearly all cross-border traffic, banned foreign tourists and mobilized health workers to quarantine anyone with symptoms. But the Kaesong lockdown is the first such known measure taken in a North Korean city to stem the pandemic.