Somalia has not had an effective government since Mohammed Siad Barre was overthrown in 1991.
The Islamic Courts Union seized Mogadishu from the control of warlords in June 2006.
The transitional government, along with Ethiopian troops, defeated the Islamic Courts in late 2006.
About 6,500 people were killed in violence in Mogadishu in 2007.
The 250,000 civilians camped outside Mogadishu are considered to be the world's biggest group of internally displaced people.