Troops from Democratic Republic of Congo and Rwanda have been firing at each other across their shared border in the eastern Congolese city of Goma, where Rwandan-backed rebels launched an offensive,

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, has seized the city of Goma, terrifying its people, many of whom sought shelter there after fleeing the rebel advance.