Somalia has been without a functioning central authority since 1991 when ruler Mohamed Siad Barre was ousted.
It touched off a bloody power struggle that has defied attempts to restore stability.
Efforts by the nearly three-year-old interim government to exert control over Mogadishu have been hindered by the near-daily attacks against its officials, Ethiopian troops and African Union peacekeepers.
Ethiopian troops backed Somali forces to drive out fighters from the Islamic Courts Union at the start of the year, and their continued presence has angered many Somalis.
In Addis Ababa, Meles Zenawi, Ethiopian prime minister, said the surge in attacks had delayed the withdrawal of his troops.
"We had reached the final phase of withdrawal from Somalia, but as insurgents regrouped under anti-peace elements' support, our withdrawal and full AU deployment is impossible for the time being," he told parliament.