South Korea's daily new coronavirus cases remained in the 300s for the third straight day Tuesday due to fewer testing over the weekend, as the country's schools opened a new semester amid lingering concerns over potential upticks.

The country reported 344 more COVID-19 cases, including 319 local infections, raising the total caseload to 90,372, the Korea Disease Control and Prevention Agency (KDCA) said.

The tally was slightly lower than the 355 recorded Monday and 356 on Sunday, apparently due to fewer tests over the weekend.

The country added one more death, raising the total to 1,606. The fatality rate was 1.78 percent. While the latest figures mark a sharp decrease from more than a thousand daily cases reported in late December and the country launched a mass vaccination campaign last Friday, the country extended the current social distancing rules for another two weeks Monday.

The greater Seoul area, home to about half of the nation's 52 million population, is under Level 2, 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.

The school attendance cap is set at one-third for elementary and middle schools under Level 2, but it can be relaxed to two-thirds depending on the situation of the pandemic.

South Korea also plans to hold a public hearing Friday before revamping the current distancing scheme to ease burdens on small business owners.

Cluster infections at workplaces, hospitals and risk-prone facilities have also continued to hamper the country's antivirus efforts.

Authorities are closely monitoring the spread of more contagious COVID-19 variants as well. As of Monday, health authorities have confirmed 156 of such cases.

The country began its COVID-19 vaccination campaign Friday by administering the vaccine developed by AstraZeneca to health care workers and patients aged under 65 at nursing homes and hospitals. It also gave the first shots of the Pfizer vaccine to front-line medical workers over the weekend.

The country said it is considering adopting so-called vaccine passports for those who have received the jabs, although it will take some time for the policy to become implemented.

"Even if people are inoculated, we do not have enough data (on the effectiveness of vaccines), and they can still lead to asymptomatic infections," said Yoon Tae-ho, a senior official at the Ministry of Health and Welfare.

The country administered 1,442 vaccine shots Monday, raising the total vaccinations to 23,086, according to the KDCA. AstraZeneca's vaccine accounted for 22,191, while Pfizer's took up 895. The country aims to achieve herd immunity by November.

A total of 156 cases of side effects after vaccinations have been reported so far, although all of them had just mild symptoms such as fever.

Of the locally transmitted cases, 120 additional cases were reported in Seoul and 111 in Gyeonggi Province that surrounds the capital. Incheon, 40 kilometers west of Seoul, identified 10 new cases.

The southeastern port city of Busan reported 17 more, while Daegu, located 302 kilometers southeast of the capital city, added 12 cases.

A boiler factory from Asan, South Chungcheong Province, also added five more patients, raising the total caseload to 203.

A call center in Gwangju, 330 kilometers south of Seoul, has reported 69 cases so far.

The country also identified some 80 new cases among 4,000 foreigners who were tested from Dongducheon, north of Seoul. More investigation is in progress.

The country added 25 imported cases, increasing the total to 7,088.

The United States accounted for nine, while patients from Indonesia and Pakistan took up three each.

The number of seriously or critically ill COVID-19 patients was 135, up four from the previous day.

The total number of people released from quarantine after making full recoveries stood at 81,338, up 268 from a day earlier. Around 90 percent of the patients reported here have been cured.

South Korea has carried out 6,681,976 COVID-19 tests so far, including 16,221 from the previous day. (Yonhap)