Tens of thousands of people have fled the Somali capital, Mogadishu, after days of intense violence said to be the worst in 15 years, the UN has said.
Ethiopian forces are supposed to be replaced by peacekeepers
Many used a lull in the fighting to flee the city on Monday, after four days of Ethiopian troop attacks on Islamist insurgents and local militias.
However, hundreds of extra Ethiopian troops have also arrived in Mogadishu.
Hospitals have reported scores of people killed, while residents have spoken of indiscriminate shelling.
The UN refugee agency said some 56,000 people fled Mogadishu in March, with most (47,000) leaving the city since 21 March.
A total of 96,000 people left their homes during February and March, the agency said.
Many set off on long and dangerous journeys through areas controlled by rival clans rather than stay in the Mogadishu.
Fighters hostile to the interim government have been setting up roadblocks in the capital.
Anger at Ethiopia
Mogadishu residents emailed the BBC to express their anger at Ethiopia's operations in the city and their sadness at the latest fighting.
"It is really a horrible place to be, you can hear the sounds of heavy gunshots and wounded people are in a state of helplessness," Maslax Osman said.
"Thousands are fleeing carrying their belongings. Some have no money so they are in the streets crying for urgent help from other Somalis."
African Union (AU) peacekeepers have so far been unable to prevent the fighting. A Ugandan soldier died and five others were wounded on Saturday - the first AU casualty since they began deploying.
AU troops are supposed to be replacing Ethiopian soldiers, who stepped in at the end of 2006 to support a Somali government campaign to oust Islamists controlling the capital.
Last week, Ethiopia said two-thirds of its troops had withdrawn from Somalia, and the rest would leave in consultation with the African Union.
But reports said that hundreds of Ethiopian reinforcements drove into Mogadishu on Sunday.
Ethiopian tanks, artillery and helicopter gunships have fought against rebels and clan militiamen armed with machine guns, missiles and rocket-propelled grenades.
The Red Cross has said the fighting is the worst seen in Mogadishu for 15 years.
William Spindler, of the UN refugee agency (UNHCR), said on Monday that residents of Mogadishu were now faced with four-hour queues to leave the city.
Thousands of Somalis have been forced to flee Mogadishu
Many have moved to the Lower Shabelle region around Mogadishu, he added, but at least 3,000 arrived in the Somaliland region, some 700km (435 miles) to the north.
Poor security is also hampering efforts to get help to the refugees.
"Our Somali staff in Mogadishu are trying to make their way to areas where people have fled. But the problem is that the security situation is making it difficult for humanitarian organisations to reach displaced people."
"They have little or no access to water, food, medicines or sanitation."
Despite the fighting, Somalia's interim government says it still plans to go ahead with a reconciliation meeting of elders, politicians and former warlords in two weeks' time.
The government has not been able to impose control over the country, which has been anarchic and rudderless since 1991, when ruler Mohamed Siad Barre was overthrown.