Witnesses in Somalia say Islamic insurgents attacked Ugandan forces in Mogadishu leaving at least four civilians dead.
Wednesday's attack took place in the city's K-four area, where Ugandan troops from the African Union peacekeeping force are based.
Witnesses say most of the civilians were killed when mortars landed on their homes.
A spokesman for the AU peacekeeping force says no troops were killed during the assault.
The fighting took place less than a day after the country's interim government signed a peace deal in Djibouti with some opposition figures.
The government and the moderate faction of the Alliance for the Re-Liberation of Somalia agreed to halt the fighting and to refrain from inflammatory statements.
Thousands of Somalis have died in more than 18 months of fighting between the insurgents and the Ethiopian-backed government. The Ethiopians invaded Somalia in late 2006 to help the government oust an Islamist movement from power in southern and central areas of the country.
The Islamists have the backing of the Eritrean-based opposition group.
Somalia has endured years of violence and chaos since the fall of the last stable central government in 1991.
Some information for this report was provided by AFP, AP and Reuters.