North Korea told patients with an unknown fever on Friday they had flu, not coronavirus as initially feared.
This claim comes just a day after authorities locked down the area in Ryanggang Province near China and deployed medical teams.
"It was revealed that all of the fever patients in the Ryanggang Province were patients with the flu," the state news agency KCNA stated on Friday.
KCNA said diagnostic tests of samples, the nature of the symptoms, and information gained from contract tracing led health workers to conclude that the fevers were caused by influenza.
Although lifting the lockdown, they urged residents to continue wearing masks and report any fever symptoms.
Kim proclaimed coronavirus defeated
North Korea's leader Kim Jong Un declared a "shining victory" over coronavirus in early August, just three months after the country announced its first COVID-19 outbreak.
The country has never confirmed how many people caught coronavirus because it lacks the means to conduct widespread testing.
Instead, it reported daily numbers of patients with fever, a tally that state media claimed rose to some 4.77 million.
Kim hailed the "miracle" of just 74 virus deaths. But experts cautioned the unverifiable figures seemed abnormally small for a country with such limited public health tools.
Since then, the country insisted it had no new cases.
All of these claims, plus the country's boast of having avoided any COVID cases for around two years after the pandemic's outbreak, have been met with considerable international skepticism. But they are also virtually impossible to disprove or investigate.
North Korea said the South was responsible for its COVID-19 outbreak, specifically blaming balloons sent to the north from dissidents who successfully defected south, which Seoul rejected as "groundless."