The Egyptian authorities arrested 75 suspected assailants in a security crackdown it launched on Wednesday in Northern Sinai’s city of Sheikh Zuweid, security sources said.

The security sources said that the arrested suspects were involved in several armed attacks in Sinai, including the latest where a bomb exploded at a security checkpoint in Rafah on Tuesday and killed four people.

Attacks on security personnel have risen sharply in the Sinai Peninsula since the ouster of Islamist President Mohamed Mursi on July 3 following mass protests against his rule.

The police and army intensified their presence and began a massive campaign in August to capture all assailants and restore order to the lawless region.