The desperate search for survivors in a Japanese resort town devastated by a landslide is becoming less hopeful, officials warned Tuesday, three days after the disaster that killed at least seven people.

The fate or whereabouts of 27 residents of Atami in central Japan remains unknown, a regional spokesman said, after dozens of homes were swept away on Saturday by violent waves of mud.

An aerial view from a Jiji Press helicopter shows the landslide site in Atami City, Shizuoka
An aerial view from a Jiji Press helicopter shows the landslide site in Atami City, Shizuoka JIJI PRESS / STR

More than 1,000 soldiers and rescue workers trawled through destroyed homes and waded across vast piles of mud on Tuesday as the 72 hours that experts say are crucial in the race to save lives drew to a close.

"As time is running out, it's getting tougher to rescue people, but we will continue our search, trying to save as many lives as possible," Shizuoka prefecture spokesman Takamichi Sugiyama told AFP.

Pylons were toppled, vehicles buried and buildings tipped from their foundations in the landslide
Pylons were toppled, vehicles buried and buildings tipped from their foundations in the landslide AFP / CHARLY TRIBALLEAU

The death toll from the disaster rose to seven after three more victims were confirmed dead on Tuesday, local officials said.

Helicopter images showed a bleak line of sludge and rubble snaking down a hillside district of Atami, a popular hot-spring destination.

Confirming the number of people missing after the disaster has been complicated
Confirming the number of people missing after the disaster has been complicated JIJI PRESS / STR

At one point the number of residents unaccounted for stood at more than 100, but officials said they had managed to track most of them down.

Confirming the number of people missing after the disaster has been complicated -- many families have summer homes in Atami but primarily live elsewhere, while elderly residents may have moved to care homes, local media said.

The landslide descended in several violent waves on Saturday morning during Japan's annual rainy season.

Atami reportedly recorded more rainfall in 48 hours than it usually does for the whole of July
Atami reportedly recorded more rainfall in 48 hours than it usually does for the whole of July AFP / STAFF

It followed days of intense downpours in and around Atami, which is about 90 kilometres (55 miles) southwest of Tokyo.

Pylons were toppled, vehicles buried and buildings tipped from their foundations in the disaster, which wrecked 130 homes and other buildings.

City officials said Monday they had identified one of the dead as 82-year-old Chiyose Suzuki.

Her eldest son Hitoshi, 56, told Kyodo that he regretted not bringing his mother -- who could not walk well -- with him when police told them to evacuate.

"I should have gone back and taken her out of there myself" instead of leaving her behind, he was quoted as saying.

Suzuki was taken to hospital by rescuers but died there.

Atami reportedly recorded more rainfall in 48 hours than it usually does for the whole of July, and survivors told local media they had never experienced such a strong downpour in their lives.

Scientists say climate change is intensifying Japan's rainy season because a warmer atmosphere holds more water.

In 2018, more than 200 people died as devastating floods inundated western Japan, and last year dozens were killed as the coronavirus pandemic complicated relief efforts.