MOGADISHU, Aug. 6 (Xinhua) -- Abdulkadir Yusuf Kariye, head of the Lafole Orphanage Center in Somalia, was killed by unknown gunmen Wednesday on the outskirts of the capital Mogadishu, witnesses said.

Kariye was at his home not far from the Orphanage Center when the gunmen shot him six times on the head. He was taken to hospital where he died, Juweriyo Ahmed, a witness, told Xinhua.

Kariye is the latest aid worker killed in the restive Somali capital where several other aid workers have been killed or kidnapped so far this year.

The orphanage center, where Kariye managed for more than two decades, is one of the largest orphanage centers in Somalia. The center once cared for hundreds of orphans and street children in Mogadishu and surrounding regions.

The center has not been used as an orphanage since the collapse of former Somali government in 1991. It now houses hundreds of internally displaced families on the outskirts of the capital.

Somalia is facing a humanitarian crisis caused by conflict, drought, and price rises in basic commodities.

Some 2.6 million Somalis, representing 35 percent of the population, are believed to be in need of humanitarian aid.

A huge number of internally displaced people rely on dwindling handouts from local and international aid agencies that have withdrawn most of their foreign staff and scaled down their operations after the increase in violence, particularly in south and central Somalia.

There hasn't been a functioning government in Somalia since 1991, when former president Mohamed Siyad Barre was ousted.