South Korea's new coronavirus cases fell below 100 on Saturday for the first time in four days as health authorities introduced a revised social distancing scheme.

South Korea confirmed 89 COVID-19 cases, raising the total caseload to 27,284, according to the Korea Disease Control and Prevention Agency (KDCA). One more patient died, raising the death toll to 477.

The number of daily virus cases had stayed in the triple digits from Wednesday through Friday.

Of the 89 new cases Saturday, local infections stood at 72, while the rest are imported cases.

The greater Seoul area -- home to half of South Korea's 51 million population -- accounted for 51 new cases out of 72 locally transmitted cases.

South Korea had seen a recent uptick in the number of daily cases due to sporadic cluster infections from senior nursing homes and hospitals.

Health authorities remain vigilant as such group transmissions were reported from private gatherings of families and friends.

On Saturday, South Korea reported 17 imported cases, raising the cumulated number of imported cases to 3,907.

Of the 17 imported cases, 11 were foreigners and six were South Koreans. They came from the United States, Russia, Myanmar, Afghanistan, Saudi Arabia, France, Poland, Ukraine, Hungary, Algeria, Liberia and Ghana.

The KDCA said the total number of people released from quarantine after making full recoveries stood at 24,910, up 89 from the previous day.

Also Saturday, South Korea shifted to a five-tier social distancing scheme from the previous three-tier scheme to enforce more detailed and regionally tailored antivirus guidelines while mitigating the impact on businesses.

Currently, South Korea is under Level 1, except the central city of Cheonan and the adjacent city Asan, where social distancing rules were lifted to Level 1.5 earlier this week amid a surge in COVID-19 cases there.

Level 1 -- the lowest in the five-tier scheme -- signifies a controllable level of transmission that allows people to carry on with their ordinary lives while wearing masks and following social distancing rules at designated facilities.

Under Level 1.5, use of multiuse facilities is restricted. At Level 2, the pandemic is considered to be spreading nationwide, and nonessential outdoor visits and gatherings are discouraged in the affected zones.

Level 2.5 will be put in place when the situation is considered to be exceeding the health system's routine response levels, and the government will urge the public to remain at home.

At Level 3, which will be imposed in the event that more than 800 new daily cases are reported for a week, the nation will effectively be placed on lockdown. (Yonhap)