South Korea's new coronavirus cases stayed above 5,000 for the second day in a row Thursday as authorities weigh whether to extend the current social distancing rules amid concerns over the omicron variant and critical cases.

The country added 5,037 new COVID-19 infections, including 4,930 local infections, raising the total caseload to 625,967, according to the Korea Disease Control and Prevention Agency (KDCA).

Thursday's figure is lower than 5,408 cases reported the previous day but marked a rise from 3,865 on Tuesday. It also represents a sharp decline from a daily record high of 7,849 on Dec. 15.

The number of critically ill COVID-19 patients stood at the second highest of 1,145 after reaching an all-time high of 1,151 the previous day, the KDCA said. Critical cases have stayed above 1,000 for 10 consecutive days.

The country added 73 more deaths from the pandemic, bringing the death toll to 5,455. The fatality rate stood at 0.87 percent, unchanged from a day earlier.

The bed occupancy rate in intensive care units for COVID-19 patients in the greater Seoul area stood at 68.8 percent as of 5 p.m. Wednesday, significantly down from 78.7 percent from the same time a day earlier.

A figure higher than 75 percent is considered to have surpassed the saturation point.

The country had no COVID-19 patients waiting to be admitted to hospitals for treatment as of midnight Wednesday, marking the second time since early November that the figure dropped to zero.

The country also reported 67 new omicron variant cases, bringing the total to 625. Among them, 293 omicron variant cases were imported and 332 locally transmitted.

The KDCA said South Korea began using its newly developed polymerase chain reaction (PCR) tests across the country Thursday.

The new PCR test, co-developed by the private sector in South Korea, reduces the time in detecting the omicron variant to three to four hours from three to five days.

Until now, health authorities used a PCR test that could distinguish between four variants -- alpha, beta, gamma and delta -- and conducted additional genome analysis to determine whether the case involved omicron.

The new PCR test is the first in the world that can detect all five main variants. It also demonstrated 100 percent accuracy for both negative and positive tests, according to the public health authorities.

The KDCA said the number of patients confirmed with the omicron variant could increase with the rise in testing volumes of the new PCR test.

On Dec. 18, the government reimposed a set of revised virus restrictions across the country, which will remain in effect until Jan. 2 to stem the spread of the virus.

It marks a reversal of the government's "living with COVID-19" scheme that began early last month with an aim to return to normalcy by relaxing virus restrictions in phased steps.

Under the new measures, the maximum size of private gatherings is limited to four people nationwide, from the previous limit of six in the capital area and eight elsewhere.

A 9 p.m. or 10 p.m. curfew is applied to businesses as well, depending on their type of service.

Health authorities earlier put the risk level of the pandemic in the country over the past week at the highest level for five weeks in a row. They will decide Friday whether to extend the current distancing guidelines.

Of the locally transmitted cases, Seoul reported 1,689, while 1,448 came from the surrounding Gyeonggi Province and 316 from Incheon, 40 kilometers west of Seoul.

The KDCA said 107 cases came from overseas, raising the caseload to 17,226.

As of Thursday, 86 percent of the country's 52 million people had received their first shots of COVID-19 vaccines, and 82.7 percent had been fully vaccinated, while 33.4 percent had gotten booster shots, the public health agency said. (Yonhap)