The national toll of 433 is the highest outside China apart from the Diamond Princess cruise ship in Japan
South Korea is facing a "grave" situation from the coronavirus outbreak, Prime Minister Chung Sye-kyun said Saturday as the country reported 229 new cases in the sharpest spike in infections yet.
Many of new cases involved patients being treated in hospital for mental health issues but also included a Samsung employee and eight people who had just returned from a trip to Israel.
The national toll of 433 is the highest outside China apart from the Diamond Princess cruise ship in Japan, with the jump in cases at the hospital in the southern city of Cheongdo following a similar spike among members of a religious sect in the nearby city of Daegu.
"The government believes the situation of the Covid-19 infections is turning into a grave phase, and is making every effort to prevent the spread," the prime minister said in a national address late Saturday.
He called on Koreans to refrain from attending large gatherings including religious services to help curb the spread of the virus. Chung also warned that the government would act firmly against people hoarding face masks or taking part in now-banned mass rallies.
Among the new cases was a Samsung Electronics employee at a plant in Gumi, 200km southeast of Seoul and close to Daegu, leading the tech giant to say it would suspend operations there until Monday.
Meanwhile, 95 of the newly confirmed cases were "related" to patients or staff at Cheongdo Daenam Hospital in Cheongdo, the Korea Centers for Disease Control and Prevention (KCDC) said.
"Most of the hospital's patients who have been diagnosed are those who had been staying as inpatients for mental illnesses," vice health minister Kim Gang-lip told reporters.
Some cases show "no confirmed epidemiological connections", meaning they are not sure where or how they contracted the virus, he added.
Authorities reported another death on Saturday, taking the toll to two. Both victims had been inpatients at the hospital.