North Korea has informed the U.N. health agency that it remains free of COVID-19 after screening an additional 1,421 people, as state media has called for strengthened anti-virus measures to confront the new Omicron variant.

According to the World Health Organization data, the DPRK conducted the polymerase chain reaction (PCR) tests during the two-week period from Nov. 12-25. The tests carried out from Nov. 19-25 covered 128 people with flu-like illness or severe acute respiratory infections and 579 health care workers.