Rwanda-backed rebels claimed they captured eastern Congo’s largest city, Goma, early Monday, as the United Nations described a “mass panic” among its 2 million people and Congo’s government said the rebel advance was a “declaration of war.

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.

Rwanda-backed M23 rebels faced pockets of resistance from army and pro-government militia overnight after entering eastern Congo's largest city Goma in the worst escalation of a conflict that has run for more than a decade.