Egyptian riot police clashed with protesters angry over an anti-Islam film blocks away from the U.S. Embassy in Cairo as the president went on state TV and appealed to Muslims to protect embassies, trying to patch up strained relations with the United States. Several hundred protesters massed in Cairo's Tahrir Square after weekly Muslim Friday prayers and tore up an American flag, waving a black, Islamist flag. When protesters tried to move toward the embassy, several blocks away, they were confronted by lines of police who fired tear gas. "With our soul, our blood, we will avenge you, our Prophet," they chanted. Ahead of the clashes, Islamist President Mohammed Morsi spoke for more than seven minutes on state TV, his most direct public move to contain protests since an angry crowd assaulted the embassy Tuesday night, scaling its walls and tearing down the American flag. "It is required by our religion to protect our guests and their homes and places of work," Morsi said. "So I call on all to consider this, consider the law, and not attack embassies, consulates, diplomatic missions or Egyptian property that is private or public."