Twelve people have been killed in clashes between combined Ethiopian and Somali government soldiers and Muslim fighters in Mogadishu.
The Ethiopian-backed forces launched raids on Sunday in the Somali capital's southern Wardhigley district, sparking fighting in which the rivals attacked each other with artillery.
"The Ethiopians and Somali forces were firing mortars and anti-aircraft weapons," Mohammed Ali Hussein, a witness, said.
Abdi Hashi, a Somali government security official, confirmed the fighting, but could not provide a death toll.
"There was fighting this morning and for sure it caused casualties, but I can't tell you how many people died," he said.
Face to face combat resulted in the deaths of both government soldiers and anti-government fighters of the Islamic Courts' Union.
Somalia has been plagued by bloody conflict since the 1991 overthrow of Mohamed Siad Barre, the then Somali president, while numerous UN-backed initiatives have failed to restore stability in the nation of 10 million people.
Journalist killed
In another development, a local Somali journalist who worked part-time for the British Broadcasting Corporation (BBC) died after being shot by suspected Muslim fighters.
Nasteh Dahir, 36, was shot dead outside his home in the port of Kismayo, about 500km south of Mogadishu. He later died in hospital.
"Unknown assailants shot and seriously wounded him as he was going to his house," Mohamed Aden, a family member, told the AFP news agency.
"Dahir later died of his injuries."
The BBC in Kenya confirmed Dahir's identity.
"We are shocked by what has happened and are trying to ascertain further information," a BBC spokesman in London said.
Dahir, who worked as a freelancer for the BBC as well as other news agencies, was the vice-president of the National Union of Somali Journalists (NUSOJ), a Somali-based press rights group.