More than 1,000 people have been killed in recent clashes in the Somali capital, Mogadishu, according to elders from the city's main clan.
Many of those killed and injured were civilians
Hawiye clan spokesman Hussein Aden Korgab also said more than 4,000 had been injured in some of the heaviest fighting in 15 years.
The clashes came as the government and Ethiopian soldiers battled insurgents - both Islamists and Hawiye fighters.
Meanwhile, Eritrea has confirmed that a Somali Islamist leader is there.
The Union of Islamic Courts was driven out of Mogadishu in December by an alliance of Somalia's transitional government and Ethiopia.
Eritrea, Ethiopia's regional rival, has always denied backing the Islamists but has now admitted that Islamist leader Sheikh Sharif Ahmed has held talks with President Isaias Afewerki in Asmara.
"We are not all prepared to allow invaders to trample upon our sacred rights and bring us under submission," he said, according to a statement on the website of Eritrea's information ministry.
Somalia has not had an effective national government for 16 years.
War crimes probe
BBC Somali service editor Yusuf Garaad says the figure of more than 1,000 dead does not come as a surprise as heavy artillery were used in residential areas during the fighting.
Most of the clashes took place near the main stadium in Mogadishu and al-Kamin neighbourhood in the south of the capital, according to human rights groups.
"We assessed battle fields, spoke to civilians, visited hospital and areas that were affected by the clashes," Mr Korgab told the AFP news agency, explaining how the clan elders reached a figure for the number of casualties.
African Union troops are supposed to replace the Ethiopians
The United Nations refugee agency says some 124,000 people have fled the city.
Last week, US Assistant Secretary of State for African Affairs Jendayi Frazer while on a visit in Somalia accused Eritrea of destabilising Somalia, by backing the insurgents.
Ms Frazer who met the president and prime minister in Baidoa, called for a permanent ceasefire to be established through dialogue between the interim government and affected communities.
The European Union representative in the Kenyan capital, Nairobi, Eric van der Linden, has called for investigations to establish if the Ethiopian and Somali forces committed war crimes during the fighting.
Hawiye clan elders and commanders from Ethiopian forces are expected to hold further talks on Tuesday about their implementing the ceasefire they agreed last week.
But fears are high that fighting could be imminent following reports that both sides have been digging trenches in parts of the city they control.
African Union (AU) troops are supposed to be replacing the Ethiopian soldiers but so far only 1,200 Ugandans have arrived, of the planned 8,000-strong force.