Congo has severed diplomatic ties with Rwanda as fighting between Rwanda-backed rebels and government forces rages around the key eastern city of Goma.

M23 insurgency in eastern Congo has intensified in January with the rebels seizing control of more territory than ever before, prompting the United Nations to warn of the risk of a broader regional war.

Congo severed diplomatic ties with Rwanda as violent clashes between Rwanda-backed rebels and government forces raged around the key eastern city of Goma, leaving at least 13 peacekeepers and foreign soldiers dead and displacing thousands of civilians.

The M23 armed group has seized further territory in the east of the Democratic Republic of Congo and on Thursday was continuing to tighten its grip on provincial capital Goma, which is almost surrounded by fighting.

M23 insurgency has intensified, with the Rwanda-backed rebels seizing control of more territory than ever before, prompting the U.N. to warn of the risk of a broader war. South Africa said nine of its peacekeepers were killed in fighting.

Congo has severed diplomatic ties with Rwanda amid intensifying M23 insurgency and ongoing battles. Allegations of Rwanda's involvement in the conflict have been denied by Rwanda, but tensions rose with the killing of a Congolese military governor.

Panic spread in Goma on Thursday, with M23 rebels steadily inching closer to the city in eastern Congo as they battle the Congolese army. Bombs were heard going off in the distant outskirts and hundreds of wounded civilians were brought in to the main hospital from nearby towns and villages.

M23 has made significant territorial gains in recent weeks, encircling Goma, which has around two million people and is a regional hub for security and humanitarian efforts. View on euronews