Police say the four Australian citizens had received training in Somalia and were planning to attack a military barracks in Sydney.
Tuesday, battles between government forces and Islamist militias in Mogadishu killed seven civilians. Experts say some of the militias might be open to dialogue with President Sharif.
Like the Somali-American from Minnesota who was killed this weekend, Tawakal Ahmed was recruited through mosques in Kenya to fight for Islamic militants in Mogadishu.
Five hundred people are arriving daily at an overcrowded aid camp in Kenya. Fighting has driven more than 159,000 from Mogadishu.
It has massed troops on the Somali border. Islamist militias have threatened retaliation if Kenya acts.
Some armed groups who adhere to a more moderate interpretation of Islam have begun battling Al Qaeda-linked extremists.
Less than a year after fleeing in the face of an Islamist insurgency, Ethiopian forces have come back to help prevent a moderate government from collapsing at the hands of militant Islamists.
The fiery Sheikh Dahir Aweys may be ready to hash out a peace deal, following weeks of fighting the moderate government of Sheikh Sharif Ahmed.
The self-declared republic of Somaliland has elections, a strong economy, and zero tolerance for extremists or pirates. But no one recognizes it.