Heavy rains pounded South Korea for a third day on Friday in a deluge that has killed at least four people, forced thousands of people to evacuate their homes and destroyed property and infrastructure.

Warnings of torrential rain remained in effect for most of the country's western and southern regions and the weather service advised extreme caution, with landslides and flooding possible through Saturday.

More than 5,000 people were evacuated at one time, but the number of people in shelters had fallen to 3,297 as of 11 a.m., the Interior and Safety Ministry said.

Rainfall of more than 400 millimeters hit some southern regions, including in the city of Gwangju, in the 24 hours to early Friday, the ministry said. Thursday's downpour in Gwangju was the highest daily total in 86 years.

Four people have died in the rains and two were missing, the ministry said. Two were trapped in cars on flooded roads and another died in a basement under floodwater in the central South Chungcheong province, it said.

A driver was killed after a 10-meter-high roadside wall collapsed on top of a moving vehicle on Wednesday in Osan, some 44 kilometers south of Seoul, fire agency officials said.

President Lee Jae Myung has called for a stronger government role in disaster prevention and response, saying that while natural disasters are hard to prevent, more can be done to anticipate damage and warn the public.

"I see there were cases where casualties occurred because of a poor response when the situation was reasonably predictable," he said at an emergency meeting on Friday, calling for all available resources to be deployed.