The death toll from three days of heavy rain and flooding in southern Japan rose to 40, including 14 who drowned at a riverside nursing home, as rescuers searched for 10 missing people and rain threatened wider areas of the main island of Kyushu.

Army troops and other rescuers worked their way through mud and debris along the flooded Kuma River, where many houses and buildings were submerged nearly to their roofs.

The Meteorological Agency issued the highest weather warning for three prefectures in northern Kyushu after heavy rain hit the island"s southern region over the weekend.

More than half a million people were advised to evacuate across Kyushu, including riverside towns in Kumamoto city where 40 bodies were recovered.

The evacuation was not mandatory and many people are believed to have opted to stay at home because of concerns over catching the coronavirus, even though officials said shelters were adequately equipped with partitions and other safety measures.