Rwandan-backed rebels moved to tighten their grip on the strategic city of Goma in the east of the Democratic Republic of Congo on Monday in what Kinshasa described as “a declaration of war” by its neighbour.

Gunfire rang out early on Monday across parts of Goma, the largest city in eastern Congo, hours after Rwanda-backed M23 rebels said they had taken control of the city despite the United Nations Security Council's calling for an end to the offensive.

Rwanda-backed rebels claim they have captured eastern Congo’s largest city, Goma, as the United Nations describe a “mass panic” among its 2 million people and Congo’s government say the rebel advance was a “declaration of war.