Southern African leaders meeting in Johannesburg have called for an immediate ceasefire in DR Congo.
The UN reports fresh fighting broke out between rebels and government forces on Sunday near Ngungu, 60km west of the regional capital, Goma.
It says fighting lasted for six hours, starting before dawn.
Fighting in the eastern Congo between rebel and pro-government forces flared up in August, in violation of a January ceasefire. It is so far limited to the province of Nord-Kivu.
Elsewhere in Nord-Kivu province: Kibati, to the north of Goma, was quiet for the second day running, after clashes Friday. A buffer zone of about 1km separates the two sides.
The conflict is rooted in the genocide of 800,000 Tutsis and Hutus in Rwanda in 1994.
The emergency summit of the Southern African Development Community was originally called to tackle the Zimbabwe political crisis.