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.

Gunfire rang out early on Monday across parts of Goma, the largest city in eastern Congo, hours after Rwanda-backed rebels said they had seized the city despite the United Nations Security Council's calling for an end to the offensive.

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.