South Korea's health authorities are raising their guard against an increase in new virus cases, as the country reported yet another cluster infection Friday after easing social distancing.

The country detected 12 more cases of the new coronavirus Thursday, most of which came from overseas, bringing the nation's total infections to 10,822, according to the Korea Centers for Disease Control and Prevention (KCDC). The tally marked new daily cases of more than 10 for the first time in five days.

But health authorities said an additional 13 cases were reported Friday, marking yet another cluster infection.

All of Friday's new infections were linked to a virus patient who visited three clubs in Seoul's popular multicultural neighborhood of Itaewon on Saturday, just days before the country shifted toward 'everyday life quarantine.'

So far, a total of 15 cases have been linked to the virus patient, according to health authorities.

At least 1,500 people are estimated to have visited the three clubs during the time when the patient visited, from midnight to 4 a.m. The patient did not wear a protective mask inside the clubs, according to the health authorities.

"It is highly likely that there are more cases down the road," Vice Health Minister Kim Gang-lip said, urging people who visited clubs in Itaewon on early Saturday to stay home and contact the authorities if they have symptoms of COVID-19.

Health authorities decided to add some strings to the new quarantine scheme. Entertainment facilities will be requested to suspend their operations for a month, effective as of 8 p.m. later in the day. But the administrative order is not mandatory.

Starting Wednesday, the country gave the go-ahead to the normalization of public facilities and other business establishments under the condition that they follow basic sanitation measures.

Preparations to reopen schools next week are under way. High school seniors will return to school Wednesday, while students in all other grades will go back by June 1.  

Health authorities have remained concerned over possible cluster infections from the holiday that ran from April 30 through Tuesday, as many South Koreans made short trips across the nation.

The incubation period of the COVID-19 virus is roughly two weeks.

"Group infections can happen not only at entertainment facilities but from all enclosed and crowded places," KCDC Director-General Jeong Eun-kyeong said. "Citizens should keep in mind that loosened awareness can lead to another cluster infection."

The country has detected 1,118 imported cases so far, with more than 90 percent of the patients being South Korean nationals.

The nation's death toll remained unchanged at 256, the KCDC said.

The overall fatality rate reached 2.37 percent. The rate for patients aged 80 and above stood at 25 percent, the KCDC said.

In total, 9,484 people in South Korea have recovered from the virus, up 65 from a day earlier, which means nearly 88 percent of the patients here have been cured.

South Korea has been carrying out tests on 654,863 people since Jan. 3, including 5,475 from a day earlier.

The number of relapse cases came to 369 as of Friday.

Health authorities have repeatedly stressed that the downward trend of new infections does not indicate that the country has fully eradicated the pandemic.

Jeong said South Korea will take various factors into consideration if it chooses to shift back to an intense social distancing scheme, adding that the number of daily new patients will not be the sole factor. 

With a second wave of the pandemic anticipated to hit the country hard again later this year, health authorities say people will need to continue wearing protective masks and following guidelines. (Yonhap)