CAIRO — Egyptian security forces quickly put down scattered protests Friday as an attempt by Islamists to hold the first major antigovernment rallies in months fizzled, with at least two protesters and three army and navy officers killed in separate incidents. The call for nationwide rallies to topple the government marked the first attempt in months to hold large protests in the face of a massive crackdown since the military’s ouster last year of Islamist President Mohammed Morsi. After Friday prayers, two civilians were killed in the eastern Cairo neighborhood of Matariya, where security forces clashed with protesters, according to the Health Ministry. Armored vehicles deployed across the city while cement blocks sealed off roads leading to security headquarters, the presidential palace, the Ministry of Defense and the main Cathedral.