Rwanda-backed rebels claimed on Monday they captured eastern Congo’s strategic city of Goma, the hub of a region containing trillions of dollars in mineral wealth that remains largely untapped.

The latest fighting has intensified a humanitarian crisis, displacing more than 400,000 people since the start of the year, and raised fears of sparking a regional war, the U.N. has warned.

Dead bodies lay in the streets, gunfire rang out and hospitals were overwhelmed in east Congo's largest city on Tuesday, as M23 rebels backed by Rwanda faced pockets of resistance from army and pro-government militias.