Analysts say the deadly march by Rwanda-backed rebels across eastern Congo could widen into a regional conflict drawing in even more countries, and the two nations most involved in the mineral-rich area might be the key to stopping the violence.

Thousands of families have been displaced by violence in eastern Congo, where Rwanda-backed rebels last month seized the key city of Goma in a blitz offensive in the mineral-rich region.

Rwandan-backed M23 rebels have seized control of a mining town in eastern Democratic Republic of Congo's South Kivu province, eight sources said on Wednesday, in an apparent violation of a unilateral ceasefire they declared this week.