Health authorities expressed concerns over how intensive care units(ICU) at hospitals will be further affected if the number of severe COVID-19 patients continues to rise.

In an online briefing Tuesday, senior health ministry official Park Hyang said that if critically ill COVID-19 patients surpass one-thousand, more beds will need to be secured for them which could seriously impact other ICU patients.

The number of severe cases rose to a new record on Tuesday to 906, after remaining in the 800s for six days. Park said 40 to 50 percent of ICU beds at hospitals nationwide are being used for COVID-19 patients.

The two biggest threats in managing severe cases and deaths were the spread among unvaccinated people and breakthrough cases among the elderly, Park said. She urged people to get vaccinated or booster shots.

Only eight percent of the adult population are unvaccinated, but this group accounts for over 51 percent of severe cases and nearly 54 percent of deaths.