Three army conscripts and one police conscript were killed Thursday morning in a car bomb attack targeting a security checkpoint in the volatile Northern Sinai Peninsula, Egypt’s state news agency MENA reported.

The explosion, which took place south of El-Arish town, also left four injured.

Militants have stepped up their attacks against security forces since Islamist president Mohamed Morsi was ousted by the military in July, following mass protests calling for him to step down.

Wednesday evening, four army soldiers were injured when their bus drove by a roadside bomb set by alleged militants in the central Sinai region, according to MENA. 

A bomb also exploded in an empty military intelligence office in the town of Rafah, bordering the Palestinian Gaza Strip, AFP reported.

Most of the attacks have been taking place in the restive Sinai Peninsula, but police stations and state installations have come under assault nationwide.

On Monday, in an unprecedented attack, assailants fired rocket-propelled grenades at a satellite communication dish in Cairo's upscale district of Maadi.