Four more South African soldiers have been killed in fighting with M23 rebels in the Democratic Republic of Congo, the government said, taking the number of South African peacekeepers killed to 13 since the conflict escalated last week.

South African troops are in Congo as part of UN and Southern African missions.

The Department of Defence said in a statement that on Monday M23 rebels had launched mortar bombs in the direction of Goma airport in eastern Congo, resulting in three SANDF (South African National Defence Force) soldiers being killed.

Another soldier injured in combat with M23 rebels over the past three days died from their injuries, it added.

Earlier the government said nine South African peacekeepers had been killed.

The defence department said on Tuesday that the SANDF remained committed to its peacekeeping duties in Congo under the UN-mandated MONUSCO and Southern African Development Community (SADC) missions.