Romanian mercenaries withdraw from DR Congo as M23 rebels tighten grip on Goma
M23 is the latest ethnic Tutsi-led, Rwandan-backed insurgency to fight in Congo since the aftermath of the genocide 30 years ago, when extremist Hutus killed Tutsis and moderate Hutus before being toppled by Tutsi-led forces under Paul Kagame. He has been Rwanda's president ever since.