South Korea's new coronavirus cases fell below 400 in about a week on Monday due to fewer tests over the weekend, but rising COVID-19 variant cases, along with pandemic fatigue, are hampering the country's virus battle amid the accelerating vaccinations.

The country reported 357 new cases, including 317 local infections, raising the total caseload to 151,506, the Korea Disease Control and Prevention Agency (KDCA) said.

Daily infections stayed in the 400s or 500s in the past five days after reporting 373 cases on June 15.

The country added two COVID-19 deaths, raising the death toll to 2004. The fatality rate came to 1.32 percent.

The KDCA unveiled its new social distancing scheme, which allows businesses to stay open longer and permits gatherings of more people.

The move came as the country's vaccination drive is gaining traction.

Currently, the greater Seoul area is under Level 2 distancing in the five-level scheme, while the rest of the country is under Level 1.5. Private gatherings of five or more are banned nationwide.

Under the new four-tier system, restaurants and cafes in the capital area will be permitted to operate until midnight under Level 2, an extension from the current restrictions of 10 p.m.

The nationwide ban on gatherings of five or more people will be lifted under the renewed guidelines, with the ceiling set to be raised to eight under Level 2. No restrictions are applied under Level 1.

In the greater Seoul area, the ceiling will initially be set at six people over a two-week transition period.

Amid the nationwide vaccination drive, a total of 15.01 million people, or 29.2 percent of the country's 51.3 million population, have received their first shots of COVID-19 vaccines. Four million, or 7.9 percent of the population, were fully inoculated as of Monday.

The country aims to inoculate 36 million with at least one jab by September to achieve herd immunity in November.

South Korea has beefed up its vaccine arsenal, currently administering two-part vaccines from AstraZeneca and Pfizer, as well as Janssen's single-dose vaccine. Moderna's vaccine is set to be given soon after completing its approval process earlier last week.

Novavax's vaccine will be introduced pending its approval.

The country has so far secured vaccines enough to inoculate around 100 million people.

Vaccination-related deaths rose eight to 298 as of Monday, but most of the accumulated 67,276 cases of side effects following inoculations were minor symptoms, such as nausea, a mild fever and headache.

Of the newly confirmed locally transmitted cases, 127 came from Seoul and 88 from Gyeonggi Province.

Incheon, located 40 kilometers west of Seoul, added seven cases as well. Daegu, 300 km southeast of Seoul, added 16 new patients, and the southeastern port city of Busan had 11 more cases.

The KDCA counted 40 more imported cases, raising the tally to 9,568. Of the imported cases, Asian countries, excluding China, accounted for 33, followed by Africa with four cases, the United States with two and Europe with one.

The number of patients in serious or critical condition came to 137, down nine from the previous day.

The total number of people released from quarantine after making full recoveries was 143,268, up 369 from a day earlier.

South Korea has carried out 10.35 million COVID-19 tests so far, including 10,413 the previous day. (Yonhap)