After Rwanda-backed M23 rebels took control of the biggest city in eastern Congo this week, the man who emerged from the shadows to assert his leadership was not the group's long-time military leader.

The cost of some essential food items has more than doubled in Goma, the main city in eastern Democratic Republic of the Congo that was captured by M23 rebels last week, according to locals and an NGO.

When M23 rebels swept into the Congolese city of Goma this week, world powers urged them to immediately withdraw. Instead, the Rwanda-backed insurgents are intent on showing they can restore order and govern.

The fragile ceasefire in eastern DR Congo is on the verge of collapse as Rwandan-backed M23 rebels reportedly seize control of Nyabibwe town in South Kivu province. The mining town, a key commercial hub between Goma and Bukavu,