The torrent of mud in the farming town of Nkubi also carried away homes, destroyed a structure owned by the local agricultural cooperative and devastated several fields, officials added.

A mother and her seven children died when the family home was "engulfed" by mudslides, said Thomas Bakenga, administrator for Kalehe territory, which includes Nkubi.

The ninth person killed was a girl at a displaced person site, he added by phone from Bukavu, the capital of conflict-hit South Kivu province.

The area around Nkubi, which is situated on the slope of a green hill, was hit by heavy rains that started on Friday.

What happened "is really a tragedy. We have told people to avoid building houses on slopes", said Bakenga.

Delphin Birimbi, the head of a local civic group, added that the structural damage was also considerable.

Torrential rains regularly cause flooding take lives in parts of DR Congo, but in recent years rain has also struck outside of the traditional rainy seasons.