South Korea's new coronavirus cases stayed below 3,000 for the second straight day Tuesday, but the number of critically ill patients hit an all-time high, raising concerns over a shortage of hospital beds for treatment.

The country reported 2,699 new COVID-19 cases, including 2,685 local infections, raising the total caseload to 420,950, according to the Korea Disease Control and Prevention Agency (KDCA).

This marked the second straight day that the daily infections remained below 3,000. The figure still has remained in the quadruple digits since July 7.

The country added 30 more deaths from COVID-19, bringing the death toll to 3,328, with the fatality rate standing at 0.79 percent.

The number of critically ill COVID-19 patients hit an all-time high of 549, up 34 from a day earlier, breaking the previous record of 522 reported last Wednesday.

The government is currently struggling to secure enough hospital beds for treatment, especially in the greater Seoul area, where around 80 percent of infections are reported.

According to health authorities, about 77 percent of beds at hospital intensive care units in Seoul and its surrounding area were occupied last week, up from 69.5 percent a week earlier.

Concerns are growing for a possible upsurge in infections amid eased social distancing rules under the "living with COVID-19" scheme launched early this month to bring the country gradually back to pre-pandemic normalcy.

On Monday, all elementary, middle and high schools nationwide resumed full-fledged in-person classes, raising worries that many unvaccinated teens could be exposed to risks of infections.

The resumption marked the first time since schools switched to learning from home or classes being held in shifts since the onset of the COVID-19 pandemic in early 2020. (Yonhap)