Floods have left 65 dead in Rwanda and heavy rains swept away scores of houses, several bridges and farms, the government said on Thursday.
The rains have caused havoc throughout East Africa.
In Kenya, floods and landslides have killed almost 200 people in the past month, while Uganda's Lake Victoria has overflowed, submerging houses, a hospital and bridges, and leaving thousands homeless.
"Heavy rains that poured Wednesday night caused a number of disasters," Rwanda's Ministry of Emergency Management said on Thursday.
The ministry said that until midnight, flooding had caused 65 deaths.
"The rains also led to damage of infrastructure such as roads," it said.
"Ninety-one houses, five bridges and several farms were swept away by the floors."
Twenty Rwandans people were killed in flooding in April.
In Kenya, four teenagers drowned on Thursday after a river burst its banks, a day after the government announced 194 people had died because of floods and landslides since the rainy season began in April.
Large areas of farmland and water infrastructure were destroyed.
Uganda's President Yoweri Museveni on Thursday wrote on Twitter that Lake Victoria was near record levels.
"Encroachers on Lake Victoria and its river banks should vacate before they are swallowed by the water because you're in its way" Mr Museveni said.
The Red Cross on Thursday said thousands of people had been displaced in the country after two rivers burst their banks, and a major hospital in western Kasese was partly submerged.
"We lost four people after the heavy rains in past four days pounded the district," Ugandan politician Alex Byarugaba from Isingiro, on the border with Tanzania, told AFP.
"Some were buried by the flash floods, which have displaced over 5,000 people."
Somalia has also had flooding in several areas, with six people killed in north-eastern Puntland last month.