More than 5,000 people are cut off by landslides as more heavy rain and floods are forecast in southwestern Japan, where the death toll from torrential downpours has risen to 24.
Landslides and fallen trees have cut roads and water supplies in the region since late Saturday, where unprecedented rainfall has fallen since Wednesday.
Television footage showed troops loading relief material such as food, water and medical supplies into military helicopters to send them to mountainous areas in Yame, Fukuoka prefecture in northern Kyushu island, on Sunday.
Local authorities were separately dispatching rescue helicopters to take patients and elderly villagers to hospital from the isolated area, where at least one person was killed, officials said.
"We will continue sending emergency ration to people there as it is still unknown when we can secure access to the area," said Kayo Shinohara, a spokeswoman for Yame City government.
"We are trying to do our best to remove rubble as soon as possible," the spokesperson told the AFP news agency by phone.
Rescue operations resumed early on Sunday in other affected areas in Kyushu, where at least eight people were still missing after a total of 24 people were confirmed dead in the landslides or floods, officials said.
Public broadcaster NHK showed rescuers continuing their search, using heavy machinery to remove uprooted trees, boulders and debris, while residents were scooping mud out of houses with shovels.
Some 3,600 people remained ordered or advised to leave their homes in southwest Japan, NHK said, after local authorities lifted similar advice to some 400,000 others by Sunday morning.
More rain forecast
The weather eased somewhat on Sunday bringing temporary relief, but the Japan Meteorological Agency warned of more heavy rain, landslides and floods on the main southern island of Kyushu.
"A peak of heavy rain in northern Kyushu has passed, but there is fear that driving rain with thunder may hit northern Kyushu as warm and humid air is flowing to the rain front," the agency said.
Meterological factors contributing to Kyushu's flash floods
"Please be vigilant of damage from landslides and floods as part of the ground has already softened and water is still overflowing from rivers because of record rainfalls," it said.
Rainfall of up to 81.7cm has been recorded in Aso, situated at the foot of a volcano, where at least 18 were killed and four others were still missing.
Television footage showed torrents of muddy, debris-strewn water and flooded houses following what officials described as "unprecedented" downpours from a seasonal rain front.
Heavy rainfall was also monitored in Kyoto, some 500km east of the affected areas in Kyushu, on Sunday, flooding more than 20 houses, news reports said.
About 20 people were temporarily trapped in the city as muddy stream broke a river bank following rainfall of nine centimetres per hour, but they were later rescued safely, the reports added.