Some 20 people are missing after a huge landslide hit Atami city in central Japan, officials say.

TV footage showed a torrent of mud plummeting down a hillside in the city southwest of Tokyo. Several houses were destroyed or buried.

The incident follows days of heavy rain in the region, national broadcaster NHK reports.

Prime Minister Yoshihide Suga is putting together an emergency task force to respond to the disaster.

Rainfall has been above the average for July for the prefecture of Shizuoka, where Atami, a hot spring resort, is located. Neighbouring Kanagawa has also been hit by unusually high rainfall.

A witness told NHK: "I heard a horrible sound and saw a mudslide flowing downwards as rescue workers were urging people to evacuate. So I ran to higher ground.

黄瀬川大橋、崩壊。
熱海で大規模土砂崩れ。
車も家も流される事態に。#豪雨　#拡散希望pic.twitter.com/HX5mKb34zj

— 炎上動画・面白ネタ拡散バード🇯🇵 (@enjou_kakusan) July 3, 2021

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The mudslide struck at 10.30 local time (01:30 GMT), according to a local resident.

Police, firefighters and members of Japan's military are involved in a search operation, according to NHK.

Residents in parts of three prefectures - Shizuoka, Kanagawa and Chiba - have been ordered to evacuate following warnings of further flooding in low-lying areas.

Japan is prone to mudslides and flooding during its annual rainy season. Dozens were killed in flooding in July last year, and more than 200 died in 2018 when parts of western Japan were inundated.