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 of Kinshasa and seek to gain political power.

M23 rebels have attacked Goma with heavy firing, killing and injuring many while forcing countless others to flee