The toll looked set to rise further in the most serious flare-up since Islamists took over the Somali capital from US-backed regional commanders a month ago.
Fighting inside the city subsided on Sunday, but clashes have erupted on a road on the outskirts of the war-torn nation's capital.
Battles broke out early on Sunday between militiamen of the Islamic courts group, which controls most of the city, and force loyal to former police chief Abdi Qaidid near Banader hospital.
The Islamic courts militiamen have surrounded the area for two weeks and closed off roads. The militia had told Qaidid's group give up its arms, but the demand was rejected.
Rival sides pounded each other with artillery, mortar and rocket rounds after Islamic militia attacked rival positions in the Medina residential district, and 16 people were wounded, witnesses told AFP.
"We have seen around 16 people who were wounded in the clashes being taken to the Medina hospital," said Hussein Bule, a resident.
The powerful courts militia routed the warlords - thought to be supported by the United States - from the capital on June 5.
The militia controls large parts of southern Somalia and has vowed the rid the country of warlords who have ruled since the government of dictator Mohamed Siad Barre was toppled in 1991.