Nine survivors were rescued from the tunnel and 11 others were believed to be missing based on reports by families or others, but the exact number of passengers trapped in vehicles wasn't immediately clear, Seo said.
South Korean rescue workers pulled seven bodies from a flooded tunnel where around 15 vehicles were trapped in muddy water, as days of heavy rain triggered flash floods and landslides and destroyed homes, leaving at least 33 people dead and forcing thousands to evacuate, officials said on Sunday.
Nearly 400 rescue workers, including divers, were searching the tunnel in the central city of Cheongju, where the vehicles, including a bus, were swamped by a flash flood Saturday evening, Seo Jeong-il, chief of the city's fire department, said in a briefing.
Photos and video from the scene showed rescue workers establishing a perimeter and pumping brown water out of the tunnel as divers used rubber boats to move in and out of the area.
Yang Chan-mo, an official from the North Chungcheong provincial fire department, said it could take several hours to pump out all the water from the tunnel, which was still filled with 4 to 5 metres (13 to 16.4 feet) of water dense with mud and other debris. Workers were proceeding slowly with the work to prevent any victims or survivors from being swept out, Yang said.
Nine survivors were rescued from the tunnel and 11 others were believed to be missing based on reports by families or others, but the exact number of passengers trapped in vehicles wasn't immediately clear, Seo said.
South Korea has been pounded by heavy rains since July 9. The rainfall had forced more than 6,100 people to evacuate and left 27,260 households without electricity in the past several days while flooding or destroying dozens of homes, the Ministry of the Interior and Safety said. At least 22 people were being treated for injuries.
President Yoon Suk Yeol, who is on a trip to Europe, discussed the rain-related casualties and damages during an emergency meeting while travelling to Poland on a train after visiting Ukraine on Saturday, according to his office. Yoon called for officials to mobilize all available resources to respond to the disaster.