Torrential rains that slammed South Korea for three days have left four people dead, two missing and more than 5,600 people evacuated, officials said Friday.

So far, most rain-related fatalities have been reported in South Chungcheong Province, according to the government's disaster response agency.

One person was found in cardiac arrest inside a flooded vehicle on a road in Seosan, South Chungcheong Province, Yonhap News Agency reported.

An elderly man in his 80s was found dead in the basement of his home, and a retaining wall collapsed onto a moving vehicle, killing the driver, officials said. Another person was found dead in a stream.

According to officials, 5,661 people from 13 cities and provinces have evacuated their homes due to safety concerns.

On Thursday, the government raised the weather-related disaster alert to its highest level, "serious," in response to the escalating damage caused by the ongoing heavy rainfall. The headquarters also activated the highest stage of its emergency response system, mobilizing all relevant government ministries and agencies for full-scale disaster response.