South Korea said Sunday it has decided to raise its alert level against the COVID-19 virus to "highest" in its latest heightened response to the confirmation of hundreds of additional cases over the weekend.

"The COVID-19 incident has been confronted by a grave watershed," President Moon Jae-in said as he publicly announced the measure. "A few days from now is a very important moment."

He said the government would strengthen the overall response system by raising the alert level by one notch to the highest of "red," speaking at an inter-agency government on responding to the outbreak that was held at Government Complex Seoul.

It's the first time that the country, traditionally known for tight quarantine measures, has raised the virus alert level to the highest in the four-tier system, in 11 years since its previous step against Influenza A (H1N1).

The measure enables the government to take such strong measures as forcibly preventing public activities or ordering the temporary closure of schools.   

The president said the government and the local authorities should not hesitate to take "unprecedented powerful" measures to contain the viral disease without being limited by "regulations."

He mentioned a minor Christian sect, known as Shincheonji. Its church in Daegu, 300 kilometers southeast of Seoul, is viewed as an epicenter of many infections reported over the past few days.

The 31st reported patient infected with the virus, a woman in her 60s, is presumed to have attended lengthy crowded worship services at the church in Daegu before testing positive for the virus last week. The number of confirmed cases in South Korea, mostly in Daegu and the nearby town of Cheongdo, shot up to over 600 as of Sunday afternoon, which includes five deaths.

Moon pointed out that health authorities are taking "special" steps in connection with the followers of Shincheonji, meaning "new world" in Korean.

The government is trying to trace all of the members for virus tests.

Closing facilities related to Shincheonji and limiting its members' activities nationwide are unavoidable measures to protect public health and safety, not seeking to restrict religious freedom, Moon said.

South Korea's fight against the virus is "utterly different" between before and after the collective infections traced to Shincheonji, Moon pointed out, adding his administration would beef up its "cooperation and support" system with local government authorities.

"The government will perceive the crisis in Daegu and North Gyeongsang Province as a national one," he said. "It will concentrate state capabilities on riding out the difficulty without sparing any support" for the regions designated as "special care zones."

He requested cooperation by Shincheonji followers as well, asking the public to refrain from engaging in collective events, both indoors and outdoors, for the time being.

"Although the situation is grave, we can overcome it," he emphasized. "The government has adequate ability and confidence to control and manage the spread of the infectious disease. Trust and cooperation are the way to win the fight against the virus." (Yonhap)