At least 51 people have died in flooding and landslides after a night of torrential rain in Bujumbura, the capital of Burundi.
The storm swept away hundreds of homes and cut off roads and power.
Police in Bujumbura said the toll was the highest in living memory from a disaster caused by freak weather, with more than 100 people also injured.
"The rain that fell in torrents overnight on the capital caused a disaster," Security Minister Gabriel Nizigama told reporters.
"We have already found the bodies of 51 people killed when their houses collapsed or were swept away."
Mr Nizigama said burials of the victims would begin immediately because there was not enough space for their bodies in the capital's mortuaries.
He was speaking at a police station in the northern part of Bujumbura, the area hardest hit by the landslides and flooding after the rains began lashing the capital late last night.
Police said several hundred homes were destroyed and more than 100 people injured in Bujumbura, which lies on the northeastern shore of Lake Tanganyika.
Houses in the poorer parts of town are often built from mud bricks, which offer no resistance to torrents of water and mud.
Mr Nizigama, touring the disaster zone with other ministers, promised food aid to those who lost their homes and said the government would bear the cost of burying relatives and would provide new housing.
Torrential rain fell solidly for ten hours overnight, causing power cuts in whole areas of the city.
The road leading out of the capital to neighbouring Rwanda was blocked because of a landslide, while a bridge was washed away on the road to the Democratic Republic of Congo.