GOMA, Democratic Republic of Congo (Reuters) -Rwandan-backed rebels marched into the centre of east Congo's largest city on Monday, witnesses said, in the latest escalation of decades of conflict in a region already suffering one of the world's worst humanitarian crises.

Rebels say they have taken control of the city of Goma in eastern Democratic Republic of Congo, although this has been denied by the government. Residents shared videos of M23 rebels patrolling Goma's main streets following a lightning advance against the Congolese army on Sunday that saw tens of thousands of people fleeing neighbouring towns.

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