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.

Rwandan backed rebels have entered the city of Goma, a key city in neighboring Democratic Republic of Congo. Could the mineral rich region be in danger of tipping into all out regional conflict?

The three-year insurgency by the Rwanda-backed rebel group M23 has intensified, and the U.N. warned the violence could spill into a wider war.