Government officials say a senior Egyptian army officer was killed while security forces arrested more than 100 Islamists ahead of planned anti-government demonstrations.

The Cabinet operations room says the officer was killed Friday when unidentified assailants opened fire from a vehicle; two army conscripts, were also injured in the attack.

Interior Ministry spokesman Hani Abdel-Latif says seven bombs were dismantled around the country.

The Islamists' call for nationwide rallies Friday is their first attempt in months to hold large protests in the face of an overwhelming crackdown since the military's ouster last year of Islamist President Mohammed Morsi.

Security forces have responded with a massive lockdown. Armored vehicles deployed across the city while cement blocks sealed off roads leading to security headquarters, the presidential palace and the Ministry of Defense.