MOGADISHU, July 18 (Xinhua) -- Thirteen people were killed and 15 others wounded Friday separately in the internally displaced people (IDPs) camps on the outskirts of Mogadishu and in clan clashes in villages in southern Somalia, witnesses and local media said.

Hooded men armed with pistols arrived while we were taking food handouts from a local aid agency and people run away, but three men who were helping with the distribution were shot dead, Baadi Elmi, a resident, told Xinhua. We do not know who they were or why they killed them.

The killing comes as IDPs in Elasha Biyaha camps have been protesting for the fourth straight day running against the targeting of aid workers.

Five aid workers have been killed recently in Somalia and four others are being held hostage by armed groups. Some aid agencies have scaled down their operations in the war-torn country while others have drawn their staff altogether after the increase in violence against aid workers.

The UN World Food Program warned Friday that attacks on aid workers on the ground and threats to ships delivering food aid to Somalia are jeopardizing the lives of millions who now need urgent food assistance.

Meanwhile, witnesses in the southern Somali port of Kismayu say that 10 militias were killed in fighting between rival clans and 15 others wounded, some of them seriously.

Local media reports say the clashes started Thursday and continued into Friday in Buriyo and Baghdad villages, 500 km south of Mogadishu, the capital.

The fighting began following revenge attacks for the killing of a member of one of the clans. Elders in the area are reportedly trying to calm the situation.