At least 18 people have been killed in gunbattles in the disputed southern Somalian port city of Kismayu, residents have said.
Hundreds were fleeing the clashes on Saturday, the first since several former warlords staked rival claims on the lucrative port and fertile hinterlands in May.
Gunmen from the Ras Kamboni armed group of Ahmed Madobe, recently self-appointed "president" of the southern Jubaland region, battled against forces loyal to Iftin Hassan Basto, another leader claiming to be president.
"Fighting started when soldiers from Ras Kamboni attacked and tried to arrest me," Basto said.
"But my men fought back and defended me."
Several rival factions claim ownership of Kismayo, a former stronghold of the Al-Qaeda-linked al-Shabab, where Kenyan troops in an African Union force are now based.
Kismayu residents counted at least 13 bodies, nearly all armed men, in the sandy streets of two neighbourhoods which witnessed the brunt of Saturday's fighting. Five people were killed a day earlier when the clashes first broke out.
"The Ras Kamboni militia now controls this part of the city," said Bile Nur, a resident of Kismayu's Calanleey district.
Residents bury dead
"Residents are burying the dead of the militia driven out while Ras Kamboni are burying theirs."
Residents hid indoors earlier as fighters riding in machine gun-mounted pick-up trucks battled for territorial control.
Businesses remained shut and the streets of Somalia's second biggest city were empty of civilians as mortar blasts rang out.
Kismayu was controlled by al-Shabab until last September when the armed groups fled an offensive by Kenyan troops supported by Ras Kamboni, an armed group loyal to a former governor of Kismayu, Ahmed Madobe.
A local assembly last month declared Madobe president of the southern Jubaland region, handing him back control of Kismayu.
But Somalia's central government, which does not view Madobe favourably, said his appointment was unconstitutional.
Within days three other men had pronounced themselves president, including Barre Hirale, a pro-Mogadishu former defence minister.
Fighting broke out when Madobe's fighters stopped another of the claimants from visiting a hotel were Somalia's defence minister and other officials were meeting.
Regional capitals and Western donors were nervous of any reversal of security gains made in Somalia by African Union peacekeepers in the fight against the al Qaeda-linked fighters, seen as a threat to stability in east Africa and beyond.
Mogadishu has said there is no going back to civil war, but government-led talks on Kismayu were being stymied by the divisive clan politics that dog Somalia.
Many residents weary of years of turmoil hold little hope for a negotiated end.