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 captured large parts of eastern Congo’s largest city including its airport, the United Nations said, as Rwanda’s president joined calls for a ceasefire

After the fall of Goma, Rwanda-backed M23 rebels are now marching towards Bukavu in DR Congo's South Kivu. The militia is aiming for the capture of capital Kinshasa city next, as per reports. The M23 rebels began their invasion of DR Congo and stormed Goma on Sunday.