Central to their campaign is the assertion that ethnic Tutsis living in DR Congo are being persecuted. Digging into the status of Tutsis in DR Congo - and how exactly this relates to the M23 uprising - is an extremely complex and sensitive matter that goes to the heart of who is considered to be Congolese.

The Rwandan-backed M23 group on Friday advanced south after seizing the biggest city in mineral-rich eastern DR Congo, in violence that according to the United Nations has killed at least 700 people in less than a week.

In a unanimous resolution, the Security Council condemned the M23 advances with the support of the Rwanda Defense Forces. US Secretary of State Marco Rubio has also called for a ceasefire in the region.