The rebels captured Mushaki and Rubaya areas over the weekend and residents have fled to escape fighting.

The Congolese army has not commented on the fall of Rubaya, a mining town located about 50km (31 miles) west of the regional capital, Goma.

The town has large deposits of coltan, manganese, tantalum and other minerals.

The M23 rebels were on Tuesday set to begin withdrawing from some territories they recently seized, according to new timelines adopted by East Africa defence chiefs.

The ongoing conflict has displaced hundreds of thousands of people in the last six months.

DR Congo has accused Rwanda of supporting the M23 group, allegations Kigali has denied.