Rescue teams battling heavy rain pulled survivors from their ruined homes on Sunday after a landslide struck the Japanese coastal city of Atami.

Authorities said an elderly couple were among 23 people rescued so far.

At least three people have been killed and dozens are still missing after a torrent of mud swept the city, south-west of Tokyo, on Saturday.

Japanese media showed footage of rescue workers searching for life in the remains of crushed buildings.

Some 80 people are still unaccounted for, according to the city mayor.

On Monday, there were about 1,500 rescue workers searching at the site, including police, firefighters and members of the military.

"We want to rescue as many victims ... buried in the rubble as soon as possible," Prime Minister Yoshihide Suga told reporters.

The Asahi news website said Yoshie Yuhara and her husband Eiji, both 75, were among those rescued on Sunday after 26 hours. They said that when the landslide hit they heard "a roaring, like heavy machinery" and fled to the top of their three-storey home just before the lower floors were inundated.

Naoto Date, a 55-year-old actor, returned to his hometown on Saturday to see the damage for himself.

"I just wanted to cry (when I saw what had happened)," he said. "Many elderly people were living there. The thought that there might be people who failed to escape from the disaster makes me really sad."

Yuta Hara, a spokesman for Atami city hall, told Reuters news agency that the rain had made the ground unstable and about 387 people had been evacuated.

Residents said the mudslide struck at about 10:30 local time on Saturday (01:30 GMT) after days of torrential rain in central and eastern Japan.

The city - a resort popular for its hot springs - saw more rainfall in the first three days of July than it usually sees in the whole month.

Meanwhile, hundreds of thousands of residents in three prefectures - Shizuoka, Kanagawa and Chiba - have been ordered to evacuate following warnings of further flooding in low-lying areas.

Prime Minister Suga, who held emergency talks with ministers on Sunday, has asked people in the worst-affected districts to stay alert and to take precautions.