The rain – which flowed powerfully – caused the Kalamu river, which runs through the city of Boma, to burst its banks on Tuesday.
It was gathered that the bodies of some of the victims had ended up in neighbouring Angola, after being carried away by the surge, while some areas of the city were buried in up to a metre of mud.
More than 1,000 houses were flooded in the city of Boma near the Angolan border, according to local authorities.
Some 10,000 people have been left homeless, the city’s mayor Marie-Jose Nsuami said.
“This is a cyclical phenomenon which happens every 10 years. It last happened in January 2015, but with climate change it’s now happened again in December 2016,” Jacques Mbadu, governor of Kongo Central province, told AFP news agency.
Waters hit a peak of 2m (six ft) above their usual level, he added.
Severe floods, droughts and storms are expected to increase as a result of climate change in Africa.
