South Korean officials sounded alarm Friday after finding more than a dozen coronavirus infections linked to club goers in the densely populated Seoul metropolitan area.
The discovery raised fears of another surge in transmissions just as the country had eased on social distancing amid a slowing caseload in past weeks.
Earlier Friday, South Korea's Centers for Disease Control and Prevention reported 12 fresh cases of COVID-19 in the 24 hours to midnight Thursday, which was the first time in five days that the daily jump came above 10.
But Vice Health Minister Kim Gang-lip said at least 13 more cases were diagnosed in the following hours, all linked to a 29-year-old patient who visited three nightclubs in Seoul's Itaewon district last Saturday before testing positive on Wednesday.
Kim said there was a "very high possibility" more infections will be confirmed as health workers are scrambling to trace the patient's contacts. He said the clubs' visitor lists show they received more than 1,500 customers combined on Saturday.
Of the 13 new cases confirmed on Friday, Kim says 12 were club goers, including three foreign nationals and one soldier, while the other was an office colleague of the patient who was first detected.
"A drop of ink in clear water spreads swiftly," Kim said during a briefing, urging vigilance to maintain hard-won gains against the virus. "Anyone can become that drop of ink that spreads COVID-19."
The country has not reported a daily jump above 100 since April 1, which allowed officials to ease social distancing guidelines, schedule the re-pening of schools and allow professional sports to return without fans in the stands.