At least 113 civilians have been killed and more than 200 injured in three days of fighting in the Somali capital, Mogadishu, a human rights group says.
The Elman Peace and Human Rights agency said it got the figures from hospitals, other humanitarian groups and counting bodies abandoned in the streets.
Heavy fighting is continuing, as Ethiopian troops clash with Somali clan militiamen and Islamist fighters.
The UN says more than 320,000 people have fled the fighting since February.
The new figure represents nearly a third of the population of the capital and is significantly higher than previous estimates.
The UN is warning of a humanitarian disaster. Most of those who have fled lack food and water and hundreds have already died from cholera and diarrhoea, UN humanitarian co-ordinator Eric Laroche said.
Correspondents say the displaced are living scattered across southern and central Somalia in appalling conditions.
There are claims the transitional government has stopped aid reaching some of those in need. The Ethiopian government strongly denies this, saying there is a need to monitor aid operations to prevent attacks.
The chairman of the Elman organisation, Sudan Ali Ahmed, said Friday was one of the worst days of shelling yet.
"We call upon the Ethiopians and the insurgents to stop fighting without any conditions. Otherwise, if they continue fighting many people will die and that is pointless," he said.
Heavy artillery was fired from the central presidential palace towards the northern insurgent strongholds of Yakshid and Heli-waa.
Many of those displaced in the fighting are women and children
Correspondents said the shelling started at 0630 local time (0330 GMT) and gained momentum through the day.
"My house was crushed, collapsed by the mortars of the Ethiopian troops," resident Isa Gedi told the BBC.
"One of my sons died. The rest of my family fled because they could not [bear to] see the flesh of my son, who is lying in the middle of the house," Mr Gedi said.
However, Somali President Abdullahi Yusuf told the BBC that the situation was slowly improving, blaming the latest violence on the Islamists.
"Our aim is to protect the public and the government from attacks of these remnants of the Union of Islamic Courts [UIC] because they are assassinating everyone to reckon with in Somalia who they think would sympathise with the government."
He also said the Ethiopians would have withdrawn by now if the violence had not continued.
Ethiopian forces have been in Mogadishu since December after helping Somalia's transitional government oust an Islamist group.
Somalia has not had an effective national government for 16 years.
The insurgents are believed to be a mixture of Islamist fighters and militiamen from the Hawiye clan - the largest in Mogadishu.
Violence has intensified this year after the relative calm when the UIC ran the city. Last month, more than 1,000 people were killed in the heaviest fighting since 1991.
The Ethiopian troops have started to withdraw, to be replaced by an African Union peacekeeping force.
But only 1,200 troops, of the 8,000 the AU says it needs, have been deployed.
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