A roadside bomb struck a passenger bus in southern Mogadishu Saturday, killing two people and injuring at least five others in the Somali capital.
Ugandan peacekeepers in Mogadishu repelled an attack by suspected insurgents earlier Saturday.
African Union spokesman Paddy Akunda said the peacekeepers suffered no casualties in the assault. But he said AU forces killed one of the attackers.
Akunda said the attack would not deter AU peacekeepers from performing their mission.
The incident comes just days after an Islamist group, known as the Shabbab, threatened to target Ugandan troops.
A Ugandan army spokesman told VOA earlier this week that the threat was being taken seriously and that the troops would defend themselves if attacked.
Five Ugandan soldiers have been killed since the 1,600 man contingent arrived in March. They were meant to be the vanguard for a planned AU peacekeeping force of 8,000, but the rest of the force has yet to materialize.
On Friday, gunmen shot and killed a Somali intelligence official as he left a mosque in Mogadishu's Yaqshid neighborhood.
National Security Service staffer Hassan Abdi Mohamed was the senior intelligence official for the neighborhood. Government troops and insurgents fought a fierce battle there last week.
Fighting between Islamist insurgents and Ethiopian troops supporting the Somali government has killed thousands in Mogadishu this year. The fighting has prompted an estimated 450,000 people ? 100,000 in the last month alone - to leave the city.