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.

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

The United Nations says Rwanda-backed rebels captured large parts of eastern Congo’s largest city of Goma including its airport.