Rwandan-backed M23 rebels advanced on Sunday into the centre of Bukavu in eastern Democratic Republic of Congo, meeting little resistance from government troops, witnesses and the armed group said, as Congo accused Rwanda of ignoring calls for a ceasefire.

The M23 armed group is advancing on strategic zones in the eastern Democratic Republic of Congo after taking two key cities, the United Nations warned on Wednesday, underscoring the threat of a regional conflict.

M23 rebels backed by Rwanda took the city of Goma in a bloody battle. This weekend, the group entered the gold-trading center of Bukavu in eastern Congo after government soldiers fled.