In Oita Prefecture, 15 people can’t be contacted and are feared missing as well, officials said.
In the two prefectures, some 700 households have been stranded after heavy rain cut access to communities, the officials said.
The government dispatched about 7,800 rescuers, including police officers, firefighters and Self-Defense Forces personnel, as the downpours triggered emergency warnings in Fukuoka and Oita prefectures.
In Asakura, Fukuoka Prefecture, a body was discovered buried under driftwood following heavy rain, while officials in the city of Hita, Oita Prefecture, said a 43-year-old man is believed to have died after being engulfed in a mudslide. The body of a 79-year-old man was also discovered in a river in the city.
A 67-year-old man in Hiroshima Prefecture remains unaccounted for. He is feared to have been swept away because he routinely checks a water channel near his home every morning to fulfill his duty to the local community, the police said.
“The government will do its utmost to save victims and take stock of the damage, placing priority on people’s lives,” Chief Cabinet Secretary Yoshihide Suga told a news conference on Thursday morning, adding that it may consider expanding the scale of the rescue effort depending on the level of devastation.
An additional 5,000 SDF members are on standby for deployment, he said.
He also said that police in the two prefectures had not yet confirmed the safety of people related to about 20 emergency calls.
The Meteorological Agency urged “utmost vigilance” in Fukuoka and Oita, saying a once-in-decades disaster is possible as atmospheric conditions remain unstable.
According to the Fukuoka Prefectural Government, the 11 people who remain unaccounted for may have been swept away. Police have confirmed the safety of three prefectural workers in Fukuoka and a man in his 60s in Oita who was reported missing on Wednesday.
As of 10:30 a.m. Thursday, about 450,000 people comprising close to 186,000 households were ordered to evacuate their homes and seek shelter. The rain also disrupted rail traffic and left up to 6,300 homes without power in Fukuoka, Kumamoto and Oita prefectures.