South Africa often uses its diplomatic heft to position itself as defender of the "global south" on the world stage, but the deaths of 13 of its soldiers in eastern Congo fighting have exposed an inability to project hard power in its own backyard.

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.

Four more South African soldiers were killed in fighting in the eastern Democratic Republic of Congo, raising the death toll to 13.

(Reuters) -Nine South African soldiers have been killed in eastern Congo's conflict zone, the South African defence department said on Saturday, as Congolese troops and peacekeepers battled to stop an advance by Rwanda-backed rebels on the city of Goma.