Islamist militias said five people had died in overnight fighting in the northern districts of Sisi and Yaqshid.
Siyad Mohamed, a militia leader linked to the Islamists, said on Friday: "It's very hard to count the wounded but the number is definitely high."
Shells crashed into homes as the rival groups fought battles using artillery, mortars and anti-aircraft missiles.
At least 80 people have been killed since Sunday, according to the International Committee for the Red Cross.
More than 200 have been injured and at least 70% of people in the worst affected areas are believed to have fled from their homes.
The street battles are the third this year between militias allied to the Islamic courts and the Alliance for the Restoration of Peace and Counter-Terrorism (ARPCT), who many Somalis believe are backed by the US.
Washington has long viewed Somalia, without an effective central government since 1991, as a haven for ''terrorists''.
Gutale Rage, a spokesman for the ARPCT, said 150 people had been killed in the fighting since Sunday.
"Fighting continued last night in Sisi; it's still raging on now. We will continue defending ourselves as long as the Islamic courts are on the offensive," he added.
Resident Abdifatah Abdikadir said the Islamic side was broadcasting radio messages urging residents to take up arms.
"The Islamic courts are urging residents to come forward and wage jihad against the alliance," Abdikadir said.
The fighting has continued despite appeals for calm from Somalia's largely powerless transitional government based in Baidoa, west of the capital.