On Saturday a suicide car-bomb attack near an African Union peacekeepers' base killed 22 people in the Somali capital.
Most of southern and central Somalia is held by Islamic insurgents and peacekeepers and government forces come under regular attack in the capital.
This bombing happened just days before Ugandan and Burundian soldiers are to be deployed to the region to strengthen the current peacekeeping contingent.
According to Mayor Mohamed Osman Ali; it remains unclear who was behind the attack.
A suspected suicide car bomb exploded about 200 meters away from an African Union base, he said. A government police officer suspected the car, which was driving at high speed, and opened fire. The suicide bomber then blew him up.
Ali said to the Associated Press that one of the dead was a police officer and the others were all civilians. Fourteen others were wounded, he said. Three of the dead were women.
AU spokesman Bahoku Barigye said no peacekeepers were wounded in the attack.
Last month, the president resigned after months of government infighting. The Somali parliament is due to choose his replacement on Monday in Djibouti.
Somalia has not had a functioning government since 1991, when a socialist dictator was overthrown by clan-based warlords.