Unknown attackers fired a mortar round near the presidential residence in the Somali capital, according to a senior police official. No one was injured. Later Tuesday, efforts toward broad-based talks to stabilize Somalia received a blow when President Abdullahi Yusuf told the Yemeni News Agency he would not hold talks with a moderate leader of Somalia's ousted Islamic movement, Sheik Sharif Sheik Ahmed, who is in protective custody in Kenya and may seek asylum in Yemen. "A single mortar round has hit near the southern entrance of the presidential palace," said Ali Sa'id Hassan Awale, the police chief of Mogadishu. Tuesday's attack was the second on or near the presidential residence since Yusuf arrived in the capital following the ouster of the Islamic movement. On Jan. 19, attackers fired three mortars into the presidential compound and then engaged guards in a 30-minute fire fight. There were no reports of casualties.