Two weeks after the nation declared victory over Covid-19, North Korea's state media reported four new fever cases on Thursday, stating they were suspected of being infected with the "malignant pandemic."
The restricted country, which has enforced a strict ban since the outbreak, acknowledged an Omicron epidemic in Pyongyang in May.
As officially recorded instances of the virus reached zero, North Korean leader Kim Jong Un, who contracted the illness during the outbreak, declared victory over it earlier this month and ordered lifting the nation's "maximum emergency epidemic prevention system."
But four new fever cases were recorded in Ryanggang province — which borders China — on August 23, the official Korean Central News Agency (KCNA) said, citing data from the state emergency epidemic prevention headquarters.
Authorities "immediately locked down the area where fever cases occurred and at the same time urgently mobilized rapid mobile anti-epidemic teams and rapid diagnosis and treatment team," KCNA said.
They are also "taking measures to probe into the cause of the fever outbreak," it said.
North Korea refers to "fever patients" rather than "Covid patients" in case reports, apparently due to a lack of testing capacity.
According to state media, it has recorded nearly 4.8 million "fever" infections and just 74 deaths for an official fatality rate of 0.002 percent. It has reported no new cases since July 29, until now.
Experts, including the World Health Organization, have long questioned Pyongyang's Covid statistics and claims to have brought the outbreak under control.
Experts say that North Korea has one of the world's worst healthcare systems, with poorly equipped hospitals, few intensive care units and no Covid treatment drugs.
It is not believed to have vaccinated any of its 25 million residents, although it may have received some vaccines from China, Seoul-based specialist site NK News has reported.
Pyongyang has blamed the outbreak on South Korea and warned of "retaliation."