South Korea's daily new virus cases spiked to the 600s on Wednesday as rising cluster infections continue to hamper the country's virus fight against the pandemic.

The country reported 676 more COVID-19 cases, including 651 local infections, raising the total caseload to 124,945, the Korea Disease Control and Prevention Agency (KDCA) said.

The daily new cases are sharply up from the 541 recorded a day earlier, the KDCA said. The number also bounced back to the 600s after three days.

The country added seven more deaths, raising the death toll to 1,847, the KDCA said.

The daily caseload has been on an upward trend over the past week.

The greater Seoul area, home to more than half of the country's 52 million people, is under Level 2 social distancing, the third highest in the five-tier scheme, with non-capital regions under Level 1.5.

Of the locally transmitted cases, Seoul reported 234 new cases, and Gyeonggi Province that surrounds the capital city identified 126 new patients, the KDCA said.

Gwangwon Province registered 48 additional cases, South Gyeongsang Province 38 cases, and Busan and Ulsan, major cities in the southeastern region, reported 22 and 21 new cases, respectively.

There were 25 new imported cases, down two from a day earlier, the KDCA said.

The number of patients with serious symptoms across the country reached 173, up 11 compared with the previous day.

The total number of people released from quarantine after making full recoveries was 114,944, up 816 from a day earlier, the KDCA said.

With an aim of achieving herd immunity by November, the authorities have been ramping up the vaccination campaign by importing more vaccines and increasing the daily inoculation cases.

A total of 3,530,014 people have received at least their first shots of COVID-19 vaccines, accounting for 6.8 percent of the country's 51.3 million population, since the country started its vaccination program on Feb. 26.

A total of 18,110 cases of side effects after vaccinations have been reported, up 625 from a day earlier, the KDCA said.

Three new deaths possibly linked to the vaccination were reported, bringing the total caseload to 88, the KDCA said.

They said the exact causes of the deaths remain unknown as they could not determine causality.

South Korea has secured enough COVID-19 vaccines to inoculate 99 million people under the COVAX Facility project and separate contracts with five foreign drug firms.

On Monday, health authorities said they will rev up the nationwide inoculation drive by shipping in more vaccines by end-June.

The country will receive 14.2 million doses of vaccines in May and June, enough to vaccinate up to 13 million people by end-June.

Earlier in the day, another batch of Pfizer Inc.'s COVID-19 vaccines for around 218,000 members of the general public aged 75 and over, and other virus-vulnerable groups arrived in the country.

The products are part of a direct contract for 3.3 million people between the US pharmaceutical firm and the Seoul government. (Yonhap)