South Korea's daily new COVID-19 cases rose above 1,300 for the third straight day Sunday, as health authorities were set to impose the toughest virus curbs in the greater Seoul area to bring the fourth wave of the outbreak under control.

The country recorded 1,324 more COVID-19 cases, including 1,280 local infections, raising the total caseload to 168,046, the Korea Disease Control and Prevention Agency (KDCA) said.

It is the first time that the nation's daily infections have risen above 1,300 for three straight days since the beginning of the pandemic. Sunday's figure compares with 1,275 on Thursday, 1,316 on Friday and 1,378 on Saturday.

The country added five more COVID-19 deaths, raising the death toll to 2,043.

Starting Monday, the government will raise virus curbs to the toughest level in Seoul and its neighboring Gyeonggi Province and Incheon for two weeks.

Under the Level 4 rules, private gatherings of three or more people will be banned after 6 p.m. and in-person classes will be closed. Weddings and funerals can only be joined by relatives. Entertainment establishments, including night clubs and bars, will be ordered to shut down, while restaurants will be allowed to have dine-in customers until 10 p.m.

As the nation is grappling with the fourth wave of the pandemic, health authorities warned the worst may be yet to come. In the worst-case scenario, the nation's daily new infections could stand at 2,140 late this month, the KDCA said. Unless things get worse, the KDCA said the average daily new infections could stand at 1,400 in late July.

If vaccinations gain pace and people strictly comply with virus curbs, the number could drop to between 260 and 415 in September, the KDCA said.

Cluster infections have recently grown at various places, including companies, schools and department stores, amid a surge in cases of the contagious delta COVID-19 variant.

About 80 percent of new infections came from Seoul and its neighboring areas, with people in their 20s and 30s, most of whom are not eligible for vaccinations, fueling new cases, according to the KDCA.

As of midnight Saturday, the rate of positive tests was 6.42 percent, up from 3.68 percent a day earlier.

The higher positivity rate means that the number of confirmed infections was higher despite fewer tests over the weekend.

About 500 people tested positive each day in Seoul. A cluster infection at a department store in Gangnam Ward has reported 109 cases so far. There were 60 infections linked to a restaurant in Seoul's Yeouido.

A total of 15.58 million people, or 30.4 percent of the country's population, have received their first shots of COVID-19 vaccines. The KDCA said 5.87 million people have been fully vaccinated, accounting for 11.4 percent of the population.

The country currently administers two-dose vaccines from AstraZeneca, Pfizer and Moderna, as well as Janssen's single-shot vaccine.

Of the newly confirmed domestic cases, 501 were from Seoul, 399 from the surrounding Gyeonggi Province and 65 from the western port city of Incheon.

There were 44 additional imported cases, with 40 of them from Asian nations.

The total number of people released from quarantine after making full recoveries was 153,760, up 607 from a day earlier. (Yonhap)