The United Nations expressed deep concern at reports of M23 rebels and Rwandan troops advancing south towards the Congolese city of Bukavu on Thursday, as the militants sought also to assert their control over east Congo's largest city Goma.

Rwanda-backed rebels who have captured eastern Congo’s largest city say they plan to take their rebellion to the capital and seek to gain political power

Rebels backed by Rwanda captured more towns in eastern Congo as fighters moved beyond the key city of Goma in an apparent attempt to expand their control in the conflict-battered region