President Moon Jae-in called on people not to lose hope in South Korea's battle against the new coronavirus Thursday as the UN health agency has declared the virus outbreak a pandemic.

"This cannot help being a big threat to us at a time when domestically we've contained the blaze of COVID-19 and sought to curb the further spread," Moon wrote on his social media. "(The global spread of the virus) could deal an unspeakable blow to the global economy and the Korean economy."

The World Health Organization declared Wednesday that the virus crisis is now a pandemic as confirmed cases are swelling across the globe.

Moon stressed what South Korea needs at this juncture is to harbor hope.

"We need the virus of 'hope' that will overwhelm COVID-19. We should also contain the virus of 'anxiety' that runs rampant like COVID-19," he said.

Moon encouraged health officials and medical workers fighting the virus and also cautioned that the outbreak may take time to be fully contained. (Yonhap)