South Korea's daily new virus cases stayed over 600 for the second straight day Thursday as the current distancing rules are likely to be again extended without clear signs of letup in the coronavirus pandemic.

The country reported 611 more COVID-19 cases, including 594 local infections, raising the total caseload to 146,303 the Korea Disease Control and Prevention Agency (KDCA) said.

Daily virus cases stayed in the 400s on Monday and Tuesday due to fewer tests over the weekend but spiked to the 600 range Wednesday.

Daily caseloads have been going through some ups and downs between the 400s and 700s in recent months due to lingering cluster infections nationwide.

The country added two more deaths, raising the death toll to 1,979. The fatality rate was 1.35 percent.

Health authorities will decide whether to extend the current distancing rules Friday. Currently, the greater Seoul area is under the Level 2 distancing in the five-level scheme, while the rest of the country is under Level 1.5.

Ahead of the planned introduction of revised distancing rules starting July, the current antivirus measures will be extended for three more weeks.

As of 4 p.m., a total of 10.45 million people have received their first shots of COVID-19 vaccines, accounting for 20.4 percent of the country's population, since the country started its vaccination program on Feb. 26. 

The KDCA said 2.41 million people, or 4.7 percent of the population, have been fully vaccinated as of 11 a.m.

Health authorities are trying to inoculate 14 million people by the end of this month and 36 million by September. The country targets to achieve herd immunity in November but hopes it can be reached earlier than expected as vaccinations pick up pace.

From Thursday to Wednesday next week, the country will administer the Janssen vaccine supplied by the US government to reserve forces, civil defense members and others in charge of defense and foreign affairs who are aged over 30. South Korea received Janssen vaccine doses for 1.01 million people last week.

Janssen's vaccine is the fourth COVID-19 vaccine product to be imported to South Korea after AstraZeneca's, Pfizer's and Moderna's. Unlike others, Janssen's vaccine only needs a single shot.

Health authorities said the Moderna vaccine is expected to be available for inoculation next week.

The government plans to offer more incentives to vaccinated people to boost its inoculation campaign. It is working to allow overseas group tours of fully vaccinated citizens to countries with stable antivirus conditions as early as in July.

"If we inoculate 25 percent of the population by the end of this month and keep up antivirus measures, we believe the number of new virus case will go down sharply after mid-July," KDCA chief Jeong Eun-kyeong said.

Of the 594 newly locally transmitted cases, 213 came from Seoul, 176 from Gyeonggi Province and 22 from Incheon, 40 kilometers west of the capital.

The southeastern city of Daegu, once the country's virus hotspot, reported 29 more cases.

Among virus clusters, a wholesale agriculture products market in southern Seoul added three more cases, raising its total to 150.

The number of cases traced to a bar in Daegu rose by 11 to 372. A restaurant for foreign workers in Changnyeong, South Gyeongsang Province, reported 17 more cases, raising its total to 85.

There were 17 additional imported cases, down four from a day earlier, raising the total to 9,237.

Of the newly identified imported cases, four came from India, followed by the United States, Kazakhstan and Indonesia with three each.

The KDCA data showed the number of seriously or critically ill COVID-19 patients was 154, up eight from the previous day.

The total number of people released from quarantine after making full recoveries was 136,713, up 539 from a day earlier, with 7,611 people being isolated for COVID-19 treatment, up 70 from a day ago. (Yonhap)