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.

Goma is on the brink of falling after M23 rebels and Rwandan troops entered the eastern Congolese regional capital. The border between DRC and Rwanda was closed, and Kenyan President William Ruto convened an extraordinary East African Community summit amidst escalating uncertainty.