South Korea's daily new coronavirus cases stayed above 400 for a second straight day on Sunday on continued cluster infections, as the number of vaccinated people topped 310,000 in just nine days since the inoculation campaign began.

The country reported 416 more COVID-19 cases, including 399 local infections, raising the total caseload to 92,471, the Korea Disease Control and Prevention Agency (KDCA) said in a statement.

New virus cases show no signs of letup due to sporadic cluster infections largely in the greater Seoul area and an increasing number of travelers amid warm weather.

Daily infections bounced back to 418 on Saturday after reporting 398 on Friday and 424 on Thursday.

The country added two more deaths from COVID-19, raising the total to 1,634. The fatality rate was 1.77 percent, the KDCA said.

South Korea reported record-high daily infections of 1,241 on Christmas last year, with the figure gradually falling since with some ups and downs.

The number, however, has stayed stagnant recently at around 300 and 400, as cluster infections from workplaces and hospitals have lingered.

Over the past two weeks, cluster infections accounted for 32 percent of new cases, while the transmission routes of 23 percent of cases remain unknown.

Health authorities remain vigilant as more South Koreans are expected to enjoy outdoor activities in the warmer weather, warning that people should continue to stay home to flatten the virus curve.

The greater Seoul area, home to about half of the nation's 52 million population, is currently under the Level 2 social distancing scheme, the third highest in its five-tier system, and other regions are placed under Level 1.5.

Private gatherings of five or more people are banned nationwide.

South Korea, meanwhile, has tentatively decided to adopt a four-tier social distancing system that allows merchants, such as cafes and restaurants, to do business under voluntary containment efforts. Health authorities plan to finalize the new social distancing scheme by the end of the month.

The country has administered vaccinations to a total of 314,656 people since launching a mass vaccination campaign last week, with an additional 17,131 getting the shots Saturday, the statement said.

AstraZeneca's vaccine accounted for 309,387, while Pfizer's took up 5,269, it said.

South Korea aims to achieve herd immunity by November.

The number of people suffering adverse effects after receiving jabs came to 3,689 so far, up 806 from the previous day. The majority of them showed common and mild symptoms such as headache or fever.

The number of people who have died after receiving the jabs came to eight so far, although their correlation has not been proven.

In authorities' extended efforts to contain the pandemic, fines of under 2 million won (US$1,771) will be issued for those who receive shots by cutting in line ahead of the scheduled vaccination plan.\

Of the 399 locally transmitted cases, 127 additional cases were reported in Seoul and 169 in Gyeonggi Province that surrounds the capital. Incheon, 40 kilometers west of Seoul, identified 27 new cases.

The three areas account for around half of the nation's 52 million population.

North Chungcheong Province reported 11 infections, Gangwon Province added 10 cases and the southeastern port city of Busan added six.

Infections linked to a sports facility in Yongin, just southeast of Seoul, reached 66, up six from the previous day.

Cases tied to a food processing company in Cheongju, North Chungcheong Province, rose one to 17, and cases related to a call center in the southwestern city of Gwangju climbed three to 76.

The number of foreigners who have tested positive in Dongducheon, north of Seoul, reached 146, according to the official KDCA data. More investigations are in progress for their families and people who came into contact with them.

There were an additional 17 imported cases, raising the total caseload to 7,177.

Of the newly added imported cases, patients from Asian countries except for China accounted for nine, while arrivals from the United States, Europe and Africa took up five, two and one, respectively.

South Korea currently requires all arrivals to hand in polymerase chain reaction (PCR) test results. Foreigners without proper documents are denied entry.

The number of seriously or critically ill COVID-19 patients was 134, down two from the previous day.

The total number of people released from quarantine after making full recoveries was 83,220, up 307 from a day earlier.

South Korea has carried out 6,843,126 COVID-19 tests so far, including 21,183 from the previous day.

The pandemic, which started in China in late 2019, has killed nearly 2.6 million people worldwide and infected more than 116 million as of March 5, data from Johns Hopkins University showed. (Yonhap)