South Korea announced its biggest spike in coronavirus infections in more than a month Monday, driven by a cluster at Seoul nightclubs and forcing authorities to delay this week's planned re-opening of schools.

The country has been held up as a global model in how to curb the virus, but over the weekend its capital -- as well as neighbouring Gyeonggi province and the nearby city of Incheon -- ordered the closure of all clubs and bars after a burst of new cases sparked fears of a second wave.

Authorities are scrambling to track down thousands of people who visited venues in the Itaewon entertainment district -- including several gay clubs.

Clubs and bars in a Seoul entertainment district have been ordered to shut down after a clustrer of infections was linked to the area
Clubs and bars in a Seoul entertainment district have been ordered to shut down after a clustrer of infections was linked to the area AFP / Jung Yeon-je

Many visitors are believed to be reluctant to come forward because of the stigma surrounding homosexuality.

The spike comes as parts of Europe begin a cautious re-opening, with health experts warning that moving too quickly will result in a surge in infection numbers.

South Korean officials reported 35 new cases Monday, taking its total to 10,909, after recording only single-digit increases for eight of the preceding 12 days -- many of them overseas arrivals.

Now 86 cases have been linked to the nightlife cluster, the Korea Centers for Disease Control and Prevention said.

Seoul authorities are urging everyone who visited a nightlife district in the city over a two-week period to get tested
Seoul authorities are urging everyone who visited a nightlife district in the city over a two-week period to get tested AFP / Jung Yeon-je

It was first thought to have been triggered by a 29-year-old man who tested positive after spending an evening at five clubs and bars in Itaewon in early May.

But the KCDC said there appeared to be multiple origins for the cluster, with director Jeong Eun-kyeong telling reporters people visited "different kinds of clubs" on "different dates".

"The majority of the visitors are not reachable," said Prime Minister Chung Sye-kyun.

"If you hesitate a single day, our daily clock may stop for a month. Please contact the nearest clinic or health centre right now."

Health officials disinfect a high school in Seoul as schools are set to re-open, firstly to high school seniors, following the government's decision to relax coronavirus restrictions.
Health officials disinfect a high school in Seoul as schools are set to re-open, firstly to high school seniors, following the government's decision to relax coronavirus restrictions. AFPTV / Yelim LEE

City authorities also urged anyone who visited the district over the past two weeks to get tested.

Seoul Mayor Park Won-soon told a radio station he will ensure their privacy, but thousands are believed to be hesitant as several establishments cater to the LGBTQ community.

Homosexuality is not illegal in South Korea, but discrimination against the community remains rampant in the conservative society, rights groups say.

Daegu, South Korea's fourth-largest city that was once the epicentre of the outbreak, on Monday also ordered the closure of all bars and clubs.

The spike in new infections came as everyday life in South Korea returns to normal, with the government relaxing social distancing rules last week.

The emergence of the cluster prompted officials to push back the re-opening of schools by one week, with students initially set to return to classes in stages starting Wednesday.

Vice education minister Park Baeg-beom said the delay was "inevitable" in order to guarantee the safety of students.

But it appeared to have brought its outbreak under control thanks to an extensive "trace, test and treat" programme that has drawn widespread praise.

Facilities such as museums and churches have reopened and some professional sports -- including baseball and soccer -- have started new seasons.

Coronavirus South Korea