South Korea reported 441 new coronavirus cases on Thursday, the highest spike in the number of single-day infections since 7 March.
The new figure took the overall caseload in the country to 18,706 and was also a triple-digit growth for 14 straight days, reports Xinhua news agency.
The number of confirmed cases for the past two weeks reached 3,936 due to infections in Seoul and its surrounding Gyeonggi province.
The cases were traced to services at the Sarang Jeil Church in Seoul and also a massive rally held in the capital city on 15 August.
Of the new cases, 154 were Seoul residents and 100 from Gyeonggi province.
Including Incheon, west of the Seoul, the total number of new infections in the Seoul metropolitan area was 313.
The infections linked to the Sarang Jeil Church totalled to 939, while those linked to the 15 August rally rose to 219.
Seven were imported from overseas, lifting the combined figure to 2,770.
One more death was confirmed, taking the death toll to 313. The total fatality rate stood at 1.67 per cent.
A total of 93 more patients were discharged from quarantine after making full recovery, taking the overall number to 14,461.
The total recovery rate was 77.31 per cent.
Since 3 January, the country has tested more than 1.86 million people.