Supporters of Egypt's ousted President Mohammed Morsi stand guard at a barricade near Cairo University, where protesters have installed their camp in Giza, southwest of Cairo, Egypt, Sunday, July 7, 2013. Egypt's new President Adly Mansour moved to assert his authority and regain control of the streets Saturday even as his Islamist opponents declared his powers illegitimate and issued blood oaths to reinstate Mohammed Morsi, whose ouster by the military has led to dueling protests and deadly street battles between rival sides.