Get all the latest news on coronavirus and more delivered daily to your inbox. Sign up here.
Cases had not exceeded 10 since last weekend when the government allowed nightclubs to reopen, highlighting the potential dangers of restarting certain businesses too early. The country has since closed more than 2,100 nightclubs.
"A drop of ink in clear water spreads swiftly," Vice Health Minister Kim Gang-lip said during a briefing. "Anyone can become that drop of ink that spreads COVID-19."
Korea Centers for Disease Control and Prevention Director Jeong Eun-kyeong said on Friday that the infected man did not wear a mask inside the clubs and that the number of infections will likely rise as health workers trace and test contacts. The clubs’ visitor lists show they received more than 1,500 customers combined on May 2.
The country's disease-control agency on Saturday reported 18 new COVID-19 cases in 24 hours the day before, while Seoul Mayor Park Won-soon on Saturday suggested the total number of infections linked to club-goers is 40. That includes 27 in Seoul, 12 in neighboring Incheon and Gyeonggi and one in the southern port city of Busan.
The Korea Centers for Disease Control, which compiles data from local governments, couldn’t immediately confirm Park’s numbers. But senior official Kwon Joon-wook raised concerns that the club-goers could possibly spread “secondary infections from wherever they live.”
South Korea was planning on allowing schools to reopen after seeing COVID-19 cases start to dwindle, but Friday's reports pushed those plans back. Now, the government is advising nightclubs, hostess bars and similar venues to remain closed until the end of May.
"At this moment, it’s too early to say whether we need to postpone the opening of schools, but we will monitor the spread of the virus and review information" from investigations of the new cases, Jeong said.
South Korea has reported more than 10,800 cases and 256 deaths from the virus. The country has received praise for its ability to contain the virus with rapid testing and contact-tracing capabilities.
The Associated Press contributed to this report.