Nine United Nations peacekeepers in eastern Congo sustained injuries during fighting with the M23 armed group, the U.N. said, as the rebels close in on Goma.

Congolese troops pushed back an attempted overnight advance by Rwanda-backed rebels on the eastern city of Goma, two Congolese army sources said on Saturday, after the sound of nearby heavy bombardment rocked the city in the early hours.

Advances being made by the M23 rebel group in the Democratic Republic of Congo are "heightening the threat of a regional war," according to U.N. Secretary General Antonio Guterres.