Fighting has intensified in the Somali capital, Mogadishu, on the third day of clashes, which have killed 49 people.
There are concerns that worse fighting is to come
An alliance of warlords and an Islamist militia are battling with mortars, rocket-propelled grenades and heavy machine guns in northern districts.
One man told the BBC that a shell had fallen on his brother's house, killing a family of four, including a baby.
This is the second round of the city's most serious fighting in a decade and there was also a clash in the south.
In March, clashes between the two sides killed at least 90 people.
The fighting started late on Sunday, when an alliance of warlords attacked the vehicle of a group allied to the Islamic courts, according to eyewitnesses.
The BBC's Mohammed Olad Hassan in Mogadishu says that a convoy of trucks with fighters belonging to one of the warlords clashed with rival gunmen operating a roadblock on the K4 junction in the south, leaving two dead.
The clash happened as they tried to get to the north of the city, where the fighting is taking place.
Hundreds of people have fled the CC district of north Mogadishu, where the fighting broke out.
Khaliif Jumale, 37, loaded his wife and three children onto a donkey cart early on Monday and said he was taking them to Afgoye, 30km (29 miles) north of Mogadishu.
"There is no reliable place here when it comes to our security," he said.
"Every corner of the city, the militias of the same rival groups have taken up positions to prepare for more lethal fighting... there is no cold place in an inferno."
The Islamic courts have restored order to some parts of the city by providing justice under Sharia - Islamic law.
The alliance of warlords recently created the Alliance for the Restoration of Peace and Counter-Terrorism.
It accuses the Islamic courts of sheltering foreign al-Qaeda leaders, while the courts say the alliance is a pawn of the United States.
Last week, Somali President Abdullahi Yusuf accused the US of funding the coalition of warlords.
The US government says it does support efforts to restore stability to Somalia but refuses to give details on who it backs and how, the BBC's East Africa correspondent Adam Mynott says.
It has an anti-terror task force based in nearby Djibouti.
Somalia has not had an effective national authority for 15 years after the ousting of President Siad Barre in 1991.
Mr Yusuf was named president in 2004 but only controls a small part of the country.
His government, temporarily based in the city of Baidoa, appealed for an end to the fighting saying it was preventing their relocation.