North Korea has reportedly locked down its capital Pyongyang for five days following rising cases of an unspecified respiratory illness, a Seoul-based news agency reported Wednesday.

South Korean NK News, which monitors North Korea cited a government notice in its report. The notice did not mention COVID-19 but said that residents in the city are required to stay in their homes through the end of Sunday and must submit to temperature checks multiple times each day.

On Tuesday, the website reported that Pyongyang residents appeared to be stocking up on goods in anticipation of stricter measures. It is unclear if other areas of the country have imposed new lockdowns.

North Korea acknowledged its first COVID-19 outbreak last year, but by August had declared victory over the virus.

The secretive country never confirmed how many people caught COVID, apparently because it lacks the means to conduct widespread testing.

Instead, it reported daily numbers of patients with fever, a tally that rose to some 4.77 million, out of a population of about 25 million. But it has not reported such cases since July 29.

State media have continued to report on anti-pandemic measures to battle respiratory diseases, including the flu, but had yet to report on the lockdown order.

On Tuesday, state news agency KCNA said the city of Kaesong, near the border with South Korea, had intensified public communication campaigns "so that all the working people observe anti-epidemic regulations voluntarily in their work and life."