In pictures: Japan searches for dozens missing in mudslide

Rescue workers dug through sludge and debris Monday looking for dozens of people who may be trapped after a torrent of mud, trees and rocks ripped with a roar through the Japanese seaside resort town of Atami, in Shizuoka Prefecture, killing at least four people.

Reuse workers search a mudslide area following heavy rains at Izusan district in Atami, Shizuoka Prefecture, west of Tokyo.

Eighty people were still unaccounted for two days after the landslide, according to Shizuoka prefectural disaster management official Takamichi Sugiyama.

Officials planned to release their names, hoping that perhaps some were away when the disaster struck, since many of the apartments and houses in Atami are second homes or vacation rentals.

Initially, 147 people were unreachable, but that number was revised downward after officials confirmed some had safely evacuated or were simply not at home.

In addition to the four people found dead, officials said 25 people have been rescued, including three who were injured.

The disaster is an added trial as authorities prepare for the Tokyo Olympics, due to start in less than three weeks, while Japan is still in the midst of the coronavirus pandemic, with cases steadily climbing in the capital and experts suggesting a need for another state of emergency.

Prime Minister Yoshihide Suga told reporters that rescue workers are doing their utmost "to rescue those who may be buried under the mud and waiting for help as soon as possible."

Three coast guard ships, and six military drones were backing up hundreds of troops, firefighters and others toiling in the rain and fog.

The landslide occurred Saturday mid-morning after days of heavy rain in Atami, which like many seaside Japanese towns is built into a steep hillside.

The landslide tore through the Izusan neighbourhood, known for its hot springs, a shrine and shopping streets. The town has a registered population of 36,800 and is about 100 kilometers southwest of Tokyo.

Shizuoka Governor Heita Kawakatsu, who inspected the area Monday where the mudslide was believed to have started, said rain soaked into the mountainside apparently weakening the ground under a massive pile of soil at a construction site that then slid down the slope. The prefecture is investigating.

Witnesses described a giant roar as a small stream turned into a torrent, and bystanders were heard gasping in horror on cellphone videos taken as it happened.

Early July, near the end of Japan's rainy season, is often a time of deadly flooding and mudslides, and many experts say the rains are worsening due to climate change. With other parts of the country expecting heavy downpours, authorities were urging people near hillsides in areas at risk to use caution.