South Korea's daily new coronavirus cases bounced back to over 700 Wednesday as the country is ratcheting up efforts to boost vaccination rates amid growing concerns over another wave of the pandemic.

The country reported 731 more COVID-19 cases, including 692 local infections, raising the total caseload to 115,926, the Korea Disease Control and Prevention Agency (KDCA) said.

Wednesday's daily caseload was sharply up from 532 cases on Monday and 549 cases on Tuesday. It is also the first time since last Wednesday that the daily tally has surpassed 700.

The average daily number of cases hovered above 600 in the past week on rising cluster infections across the nation as people increased their activities in spring, stoking concerns of another wave of the pandemic.

The country added four more deaths, raising the death toll to 1,806. The fatality rate was 1.56 percent.

South Korea decided to maintain the current level of social distancing rules through May 2 to contain the virus, while placing more restrictions on entertainment establishments, such as nightclubs and bars, but the country may adjust the alert level if infections continue to rise.

The greater Seoul area, home to half of the nation's 52 million population, is under the Level 2 distancing scheme, the third highest in the five-phase system. The rest of the country is under Level 1.5, except for some municipalities that have adopted Level 2 measures.

Private gatherings of five or more people are banned nationwide.

Since the country started its vaccination campaign on Feb. 26, a total of 1,771,407 people, or 3.41 percent of the population, have been given COVID-19 vaccine shots, including 130,228 the previous day.

AstraZeneca's vaccine has been administered to 1,093,174 people, while 678,233 received that of Pfizer.

The KDCA said 60,597 people have been vaccinated with two doses.

A total of 12,533 cases of side effects after vaccinations have been reported, up 138 from a day earlier, but 98.3 percent were mild symptoms, including muscle pain and fever.

A total of 51 deaths after vaccinations have been confirmed, according to the KDCA, up two from the previous day, although authorities have so far ruled out any link between the deaths and the vaccinations.

Health authorities are trying to speed up COVID-19 vaccinations to more people across the country, while seeking to secure stable vaccine supply.

They aim to inoculate 3 million people by the end of this month and 12 million by the end of June.

South Korea said that it has secured vaccines for 79 million people from the World Health Organization's global vaccine COVAX Facility project and pharmaceutical companies, such as AstraZeneca, Pfizer, Moderna, Johnson & Johnson's Janssen and Novavax, and targets achieving herd immunity by November.

On Tuesday, the Seoul government said it is looking at a "vaccine swap" agreement with the United States.

Pfizer vaccines for 125,000 people arrived here earlier in the day, which is part of a deal with the US pharmaceutical firm. So far, a total of 1.75 million doses of Pfizer vaccines have been shipped in.

By the end of June, an additional 5.25 million doses of Pfizer vaccines are scheduled to arrive here.

Health authorities said they were in negotiations with Moderna to secure the company's vaccines in the first half of the year amid tight vaccine supplies.

While South Korea has previously said that Moderna's vaccines for 20 million people will arrive in the country starting in the second quarter, Finance Minister Hong Nam-ki told lawmakers Tuesday that most of the company's vaccines will arrive in the latter half of the year.

Authorities said they will also closely review data on Johnson & Johnson's Janssen vaccine to determine who will receive the jabs, as the European Medicines Agency said the vaccine has possible links to rare blood clots.

South Korea has secured Janssen's vaccines for 6 million people, but they have yet to be introduced in the country.

Of the newly locally transmitted cases, 449 cases came from the capital area, with 211 from Seoul, 225 from Gyeonggi Province and 13 from Incheon, 40 kilometers west of the capital.

The southern port city of Busan, the country's second-largest city, reported 33 more cases.

There were 39 additional imported cases, up 19 from a day earlier. The country's total number of imported cases is now at 8,061.

Of the newly added imported cases, seven were from Russia followed by the United States and Kazakhstan with six each.

Health authorities are keeping especially close tabs on COVID-19 variants from overseas that are believed to be more contagious.

So far, they have confirmed 449 COVID-19 variant cases from Britain, South Africa and Brazil. In addition to the three major COVID-19 variant strains, health authorities have identified 321 cases of "emerging" variants of the novel coronavirus since December, which includes nine cases of the Indian variant.

To curb the spread of virus variants, the country decided to extend a ban on passenger flights from Britain, which has been in place since Dec. 23, until May 6.

From Thursday, all arrivals from South Africa and Tanzania are required to stay at state-designated shelters for 14 days upon their entry into South Korea.

The KDCA data showed the number of seriously or critically ill COVID-19 patients was 116, up seven from the previous day.

The total number of people released from quarantine after making full recoveries was 105,877, up 650 from a day earlier, with 8,243 people being isolated for COVID-19 treatment, up 77 from a day ago.

South Korea has carried out 8,497,594 COVID-19 tests, including 39,002 the previous day. (Yonhap)