Witnesses say al-Shabab fighters are pulling out of the southern Somali port of Kismayo, the largest city that was still in insurgent hands.
Residents tell VOA that al-Shabab leaders already had fled and that their fighters started leaving Sunday after heavy fighting with Somali and Kenyan troops. Dozens were reported killed and the commander of the Somali forces says al-Shabab has been defeated.
It is not clear where the al-Shabab fighters were heading.
News of al-Shabab's apparent defeat came as Somalia's new president, Hassan Sheikh Mohamud, was inaugurated in Mogadishu. President Mohamud called security his top priority, vowing to unite the fractured nation.
Somalia's parliament elected Mohamud last week. He survived an assassination attempt last Wednesday when suicide bombers tried to force their way into the Mogadishu hotel where he had been living. Mohamud was unharmed, but several soldiers and civilians were killed.
President Mohamud's election marks the final phase of a U.N.-backed plan to create a stable, central government, which Somalia has not had since 1991.
Somali leaders adopted a new constitution and installed a new federal parliament and speaker last month. The new government replaces an eight-year transitional government that was largely ineffective and plagued by infighting.