Article published on the 2008-08-03 Latest update 2008-08-03 15:46 TU
The bomb went off in the K4 neighbourhood on a road that leads to the presidential palace and is often used by Somali officials and Ethiopian troops, who came to the country in 2006 to support the government.
Most of the victims were women paid by local NGOs to sweep the street. Eyewitness Hasan Abdi Mohamed told the French news agency AFP that they were "torn to pieces". Other local people said that there was "blood everywhere, dead and wounded people strewn across the street".
Residents rushed to help the victims and hospitals say that they are receiving the largest number of civilians in weeks.
There was no immediate claim of responsibility. Hardline Islamist groups have often targeted military convoys in the area.
Guillermo Bettocchi of the UN's refugee organisation, the UNHCR, says there is a growing number of civilian casualties in the conflict.
"It’s got to proportions that should be stopped and I think that there’s an urgent need to stop this nonsense," he told RFI.
Ethiopian troops intervened in Somalia in late 2006, as the Western-backed transitional government fought to maintain power after ousting an Islamist militia which had controlled large parts of the country.
Islamist guerrillas have since attacked government targets, Ethiopian forces and African Union troops but civilian casualties have been in the thousands.