A two-year-old boy, a woman and a rescue worker were among the victims. The boy was pronounced dead after being buried for two hours in a landslide, The Japan Times reported citing rescue workers.
More than 100mm of rain per hour was recorded in Hiroshima prefecture in the early hours of Wednesday, triggering landslides and flooding. Residents in the areas hit by the torrential rains have been advised to evacuate to safety.
Prime Minister Shinzo Abe has cut short his vacation following reports of the disaster, and instructed government bodies to make all-out efforts to rescue those affected.