The militia seized the pivotal city of Goma, threatening a new humanitarian crisis in a region that has suffered decades of fighting.

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.

Rebels backed by Rwanda captured more towns in eastern Congo as fighters moved beyond the key city of Goma in an apparent attempt to expand their control in the conflict-battered region