A lightning advance in Congo's mineral-rich eastern borderlands is set to boost the M23 rebellion's illegal mining revenues, with analysts predicting a further surge in illicit trade in minerals including coltan and gold through neighbouring Rwanda.

Fighting between Rwanda-backed rebels and the Congolese army continued for a second day in Goma, amid calls by African leaders for an immediate cease-fire.

The M23 militia, funded and directed by Rwanda, said it had seized the city of Goma, terrifying its people, many of whom sought shelter there after fleeing the rebel advance.