The U.N. health agency says that fighting last week between Congolese government forces and Rwanda-backed rebels in the major eastern city of Goma left at least 900 people dead, raising the previously cited death toll of 773.

Fighting across the largest city in eastern Democratic Republic of Congo and "is still very much ongoing ... it's not over yet," senior U.N. official in Congo, Bruno Lemarquis, said on Monday after Rwandan-backed M23 rebels claimed to have control of Goma.

Bodies are lying on the streets. Medical staff in overwhelmed hospitals are treating hundreds of wounded civilians against the backdrop of gunfire and mortar fire.