TOKYO: Hundreds of troops joined the search in western Japan Wednesday for 10 people missing a day after torrential rains triggered floods and landslides that killed at least seven people, officials said.

Emergency services staff were digging through mud and debris at a mud-filled nursing home in Hofu, Yamaguchi prefecture, 750 kilometres (470 miles) west of Tokyo, television images showed.

"We started the search for the people still missing at 7:00 am (2200 GMT) with at least 280 rescue officers," a prefectural police spokesman told AFP.

The Ground Self-Defence Force sent 220 troops to join the rescue effort, which was hampered by muddy water still flowing down a hillside and into the nursing home.

Rescuers found a fourth body at the nursing home Wednesday afternoon, bringing the death toll to seven, a local police spokesman said, adding that three others were still missing at the mud-covered facility.

Local media reported that another body was pulled from the wrecked facility, bringing the death toll to eight, but police could not immediately confirm these reports.

Another person in his 70s was newly declared to be missing in Iwakuni, eastern Yamaguchi, on Wednesday, keeping the number of missing unchanged at 10, the spokesman said.

Two more people were killed elsewhere in Yamaguchi, one in a landslide and another in a swollen river, police officials said.

In the neighbouring prefecture of Tottori, one person drowned in a flooded river, another police spokesman said.

Some 370 people were evacuated to emergency shelters while the water supply was cut to some 30,000 households in Yamaguchi, public broadcaster NHK said, adding that more than 1,270 houses had been flooded.

Prime Minister Taro Aso had ordered thorough measures to tackle the disaster, Chief Cabinet Secretary Takeo Kawamura told a news conference in Tokyo.

"First, we have to do our best to rescue people as there are a number of people still missing," Kawamura said.