Egyptian tanks help secure the presidential palace in Cairo during a protest Thursday by opponents of President Mohammed Morsi. Egypt has the largest army in Africa and the seventh-largest tank army in the world, in part because of U.S. military aid. (Associated Press)

Egyptian tanks help secure the presidential palace in Cairo during a protest Thursday by opponents of President Mohammed Morsi. Egypt has the largest army in Africa and the seventh-largest tank army in the world, in part because of U.S. military aid. (Associated Press)