On Thursday the country said it had locked down the area and mobilised medical teams after four fever cases were reported from Ryanggang Province, but that it was not the novel coronavirus over which the country declared victory this month.

“It was revealed that all of the fever patients in the Ryanggang Province were patients with the flu,” KCNA news agency reported on Friday, saying experts conducted clinical symptoms observation, epidemiological relationship investigation and nucleic acid tests.

North Korea has never confirmed how many people caught Covid-19, 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. But it said it had registered no new such cases since July 29.