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.

President of the Democratic Republic of Congo said on Thursday that his troopers are fighting an insurgence by the Rwandan-backed militant group M23 which recently captured swaths of land in the east.