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.

The M23 militia, funded and directed by Rwanda, said it had seized the city of Goma, terrifying its people, many of whom sought shelter there after fleeing the rebel advance.

The M23 rebel group has made significant territorial gains along the border with Rwanda in recent weeks, closing in on Goma, the provincial capital.