North Korea reported four new fever cases in Ryanggang Province on Thursday, just 13 days after the country claimed victory over the COVID-19 pandemic.

Citing data from the state emergency epidemic prevention headquarters, Pyongyang’s state media said four fever cases suspected of being infected with the “malignant epidemic” occurred in Ryanggang Province in the northeastern region on Tuesday.

Instead of directly referring to COVID-19, the North has been calling the coronavirus the “malignant epidemic,” and describing patients with symptoms as those with fever.

The report comes after North Korean leader Kim Jong-un had declared victory over the COVID-19 on Aug. 10, when he ordered the lifting of the strict disease preventive measures he imposed in May.

Since July 29, the North’s daily fever tally has remained at zero.

Health authorities immediately locked down the area and are working to find the cause of the fever outbreak, the North’s official Korean Central News Agency said.

Over the four fever cases on Thursday, the state media did make the claim that authorities did not find any confirmed cases of the malignant epidemic since having declared victory against the disease.

On Aug. 11, North Korea claimed “victory” over the outbreak. According to Pyongyang’s state media, about 4.8 million people suffered from fever since May, and 75 people -- less than 0.002 percent -- died due to related symptoms. The North has also claimed that studies have shown that 93 percent of North Koreans have antibodies against COVID-19.

Experts outside of North Korea, however, have questioned Pyongyang’s claims, saying the death rate is unrealistic and Pyongyang’s tally of patients is unreliable.

Some South Korean experts have said that North Korea’s COVID-19 cases are likely to be at least double that of Pyongyang’s announcement, and the death rate is likely to be 100-fold higher based on data collected in other countries.

Pyongyang has also taken to blaming South Korea for the outbreak within its borders.

Last month, Pyongyang claimed the COVID-19 outbreak on its land originated from alien things found near the inter-Korean border, putting blame on balloon-carried materials sent by North Korean defector groups in South Korea, such as anti-Pyongyang leaflets.

The North Korean leader’s sister Kim Yo-jong has also issued direct threats against the South.

In a televised speech on Aug. 10, Kim Yo-jong said Pyongyang will “answer by exterminating not only the virus but South Korean authorities” should “dangerous actions that can lead to inflow of virus” continue, referring to the items of South Korean origin found near the inter-Korean border.

By Jo He-rim (herim@heraldcorp.com)