Three Tanzanian soldiers have been killed and three others injured after a mortar shell landed near their camp in eastern Congo, where they're deployed under the the banner of a regional bloc to help quell violence. It's unclear who was responsible for the attack on Saturday morning. It was reported on Monday by the regional bloc, the Southern African Development Community, or SADC. It said in a statement that a South African soldier also had died while being treated for undisclosed “health challenges.” President Felix Tshisekedi of Congo blames neighboring Rwanda for providing military support to rebels, an allegation Rwandan officials no longer deny. Rwanda opposes the deployment of peacekeepers from SADC, saying they are interfering in an internal problem.