South Korea’s president vowed Monday to “completely overhaul” the country’s approach to extreme weather from climate change, after at least 39 people were killed by recent flooding and landslides during monsoon rains.

Rescue workers waded through thick mud as they drained a flooded underpass in central Cheongju, searching for more victims after vehicles were trapped in the tunnel by flash floods, the interior ministry said, with nine people still missing nationwide.

South Korea is at the peak of its summer monsoon season and days of torrential rain have caused widespread flooding and landslides, with rivers bursting their banks and reservoirs and dams overflowing — and there is more rain forecast this week.

“This kind of extreme weather event will become commonplace — we must accept climate change is happening, and deal with it,” President Yoon Suk Yeol said Monday, ahead of a visit to flood-hit North Gyeongsang province.

The idea that extreme weather linked to climate change “is an anomaly and can’t be helped needs to be completely overhauled”, he said, calling for “extraordinary determination” to improve the country’s preparedness and response.

South Korea will “mobilise all available resources” including the military and police to help with rescue efforts, he said.

“The rainy season is not over yet, and the forecast is now that there will be torrential rain again tomorrow,” he added.

The majority of the casualties — including 19 of the dead and eight of the missing — were from North Gyeongsang province, and were largely due to massive landslides in the mountainous area that engulfed houses with people inside.

Some of the people who have been reported missing were swept away when a river overflowed in the province, the interior ministry said.

– Stay inside –

South Korean police said they would launch an investigation into the fatal flooding of the underpass in Cheongju, some 112 kilometres (70 miles) south of Seoul, Yonhap reported.

The underpass flooded early Saturday when a nearby river overflowed and an embankment collapsed, leaving 16 vehicles, including a bus, trapped inside, with at least 12 people killed and rescue workers warning the toll could rise as they searched the area.

The Korea Meteorological Administration forecast more heavy rain through Wednesday and urged the public to “refrain from going outside”.

South Korea is regularly hit by flooding during the summer monsoon period, but the country is typically well-prepared and the death toll is usually relatively low.

Scientists say climate change has made weather events around the world more extreme and more frequent.

South Korea endured record-breaking rains and flooding last year, which left more than 11 people dead.

They included three people who died trapped in a Seoul basement apartment of the kind that became internationally known because of the Oscar-winning Korean film “Parasite”.

The government said at the time that the 2022 flooding was the heaviest rainfall since Seoul weather records began 115 years ago, blaming climate change for the extreme weather.