Heavy rains forecast in western Japan are raising the risk of more landslides and hindering efforts to locate dozens of people still missing after several hills in Hiroshima collapsed earlier this week.

The Fire and Disaster Management Agency says 40 people are confirmed dead and 47 still unaccounted for after torrents of mud, rocks and timber swept through at least five valleys in Hiroshima's suburbs after heavy rains Wednesday, smashing dozens of houses. It says 67 people were injured.

Police say there is a chance of some inaccuracies in the tallies.

About 2,800 police and military personnel have been searching for the victims.

The disaster has prompted questions over why so many houses were built near unstable slopes and why an evacuation advisory came an hour after the first mudslide.