Unknown attackers fired a mortar round near the presidential residence in the capital on Tuesday, said a senior police official. No one was injured. "A single mortar round has hit near the southern entrance of the presidential palace," said Ali Sa'id Hassan Awale, the police chief of the capital, Mogadishu. Mogadishu has seen spiraling violence over the past month following the ouster of Somalia's Islamic movement that controlled the capital and much of southern Somalia. The ousted Islamic movement, which still has strong support in Mogadishu, has vowed to wage an Iraq-style insurgency. Clan rivalries also are a challenge for the government. Hundreds of government forces and Ethiopian soldiers who have been supporting the government have sealed off the entire area and searching house to house for those who may be responsible. "We were ordered to move away from the presidential palace, and we will lose our business in this way," said Shukri Ahmed Yare, a 32-year-old shop owner who lives near the residence.