South Korea's daily new coronavirus cases fell back below 600 on Sunday mainly due to fewer tests as health authorities try to boost the nationwide vaccination drive to contain the spread.

The country reported 564 more COVID-19 cases, including 522 local infections, raising the total caseload to 127,309, the Korea Disease Control and Prevention Agency (KDCA) said.

Sunday's figure was sharply down from 701 from the previous day.

The daily caseload usually spikes after weekends as more people get tested. The average daily virus figure neared 600 in the past week as people have increased their activities due to the warmer weather.

There were nine additional deaths from the virus, raising the total to 1,874. The fatality rate was 1.47 percent.

The country plans to vaccinate 13 million people by June and 36 million by September in order to achieve herd immunity in November.

Health authorities said some 8.95 million people aged between 60 and 74 will receive vaccination shots in the coming weeks.

Starting May 27, people aged between 65 and 74 will be administered AstraZeneca's vaccine. Those aged between 60 and 65 will receive AstraZeneca's vaccine beginning June 7.

A total of 3,674,682 people, including 11,931 the previous day, have received their first shots of COVID-19 vaccines, accounting for 7.2 percent of the country's population, since the country started its vaccination program on Feb. 26.

AstraZeneca's vaccine has been given to 2,014,012 people, while 1,660,670 have received that of Pfizer.

The KDCA said 501,539 people have been fully vaccinated, with an additional 27,546 receiving their second jabs the previous day.

A total of 19,631 cases of side effects after vaccinations have been reported, up 237 from a day earlier, although 96.4 percent of them were mild symptoms.

A total of 95 post-vaccination deaths have been reported, although the exact causes of the deaths remain unknown as they could not determine causality, health authorities said.

Of the newly confirmed locally transmitted cases, 346 cases came from the capital area, with 191 from Seoul, 144 from Gyeonggi Province and 11 from Incheon, 40 kilometers west of the capital.

The southern port city of Busan, the country's second-largest city, reported 10 more cases.

Among virus clusters, a day care center in Bucheon, west of Seoul, added five more cases, raising its total to 99.

The number of cases connected to an entertainment facility in Sacheon, South Gyeongsang Province, rose by two to 57, while infections within the foreign worker community in Gangneung, Gangwon Province, increased by three to 77.

There were 42 additional imported cases, the largest since Feb. 7 when the country reported 46. The country's total number of imported cases is now at 8,553.

India and Singapore accounted for 12 each. Five of the new cases from India came from those who returned via a special flight Friday.

The new imported cases from Singapore were reported from people on two vessels.

Health authorities are especially keeping close tabs on COVID-19 variants from overseas that are believed to be more contagious.

The number of seriously or critically ill COVID-19 patients was 160, down five from the previous day.

The total number of people released from quarantine after making full recoveries was 117,423, up 542 from a day earlier, with 8,012 people being isolated for COVID-19 treatment, up 13 from a day ago.

South Korea has carried out 9,105,771 COVID-19 tests, including 16,605 the previous day.

Daily cases, compiled by health authorities and local governments, are counted until midnight and announced the following morning. (Yonhap)