The protest was called by the Muslim Brotherhood and other Islamist groups under the theme of “rejection of military coup”. An Egyptian soldier was killed in coordinated rocket and machine gun attacks by Islamist militants on army checkpoints and a police base in the restive Sinai. Outside the Rabaa Adaweya mosque in a Cairo suburb, where Mursi supporters have gathered over the last week, the army deployed extra armored vehicles several hundred meters from makeshift barricades. Islamist fringe groups have threatened armed retribution for Morsy's overthrow. Police arrested four men Friday who allegedly planned a reprisal terror attack,