Japanese police said the death toll from rain-triggered landslides on the outskirts of Hiroshima city rose to 39 on Thursday with 51 people still missing, as search efforts continued in the devastated area.

Hillsides caved in or were swept down into residential areas in at least five valleys in the suburbs of the western Japanese city on Wednesday, crushing dozens of houses after heavy rains.

Hiroshima prefectural police said 39 people were confirmed dead and 51 others were missing as of midday Thursday. The Fire and Disaster Management Agency said 23 people were injured, 13 seriously. A police official, who spoke on condition of anonymity in line with official policy, said there was a possibility of some inaccuracies in the tally.

Japan landslide Aug.21

The search continues in Hiroshima's Asaminami ward, with 39 deaths now attributed to Wednesday's landslide, including several children. 51 people are missing and police warn the number of casualties is likely to rise. (Toru Hanai/Reuters)

A two-year-old, a 11-year-old and a firefighter are among the dead.

About 2,500 police and military personnel searched for the missing in the mud-covered areas.

Hiroshima city officials have faced criticism because their initial evacuation advisory came an hour after the first mudslide. Officials said their response was delayed because the land collapsed so quickly at multiple locations.

Landslides are a constant risk in mountainous, crowded Japan, where many homes are built on or near steep slopes. Torrential rains early Wednesday apparently caused slopes to collapse in areas where many of the buildings were newly constructed.

Hiroshima's geology, consisting of highly water-retentive soil, makes the city particularly prone to such disasters, experts say.

With files from CBC News