Congolese security forces on Tuesday tried to slow the advance of Rwanda-backed M23 rebels who say they have captured Goma after entering eastern Congo's largest city, as U.N. officials reported violence,

After three years on the run from the Rwandan-backed M23 insurgency in eastern Congo, on Sunday, with the rebels fighting their way into Goma's city outskirts, Colleta Nzambonimpa found herself in church with nowhere left to turn.

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.