South Korea on Tuesday reported the most coronavirus deaths in a single day, as critically ill patients continue to pile up amid spiking cases, health authorities said.

The Korea Disease Control and Prevention Agency (KDCA) said the country reported 13 additional deaths from COVID-19, raising the total caseload to 600.

It marks the first time that the daily death toll hovered above 10.

The number of seriously or critically ill COVID-19 patients came to 205, sharply up 20 from the previous day, according to the KDCA.

Of the total, 82 are in their 70s, followed by 53 in their 60s and 38 in their 80s, the KDCA said.

Health authorities have warned the death toll could spike in the coming days, as the fatality rate for COVID-19 patients is especially high among the older population

The average fatality rate for COVID-19 patients came to 1.35 percent, compared with a whopping 15.02 percent among those aged 80 or older, the KDCA said.

An average of 219 COVID-19 patients older than 60 were reported every day over the past week, the KDCA said. The number accounts for 32 percent of the total daily new cases, compared with 22.9 percent a week earlier. (Yonhap)