M23 rebels claim they now control the Congolese city of Goma—an act Congo's government described as a 'declaration of war.'

GOMA, Democratic Republic of Congo (Reuters) -Rwandan-backed rebels marched into east Congo's largest city Goma on Monday and troops from the east African neighbours exchanged fire over the border in the worst escalation of the long-running conflict for more than a decade.

Rwanda-backed rebels on Monday claimed they captured Goma, the largest city in the eastern part of the Democratic Republic of Congo, where the United Nations reported "mass panic" among its 2 million residents.