NORTH SINAI, Feb 3 (Aswat Masriya) - An explosive device went off after the passage of a military convoy in North Sinai's Rafah on Tuesday, leaving no casualties or losses, security sources said.

Security forces discovered another explosive device on a road south of al-Arish, which they are now dismantling, the sources added.

The explosion comes amid wide security raids in North Sinai following four simultaneous attacks in the governorate on Thursday, the deadliest in months.

Militants have escalated attacks targeting security forces in Sinai, as well as other parts of the country, since the military ouster of Islamist President Mohamed Mursi in July 2013, which followed mass protests against his rule.

At least 30 people were killed and 50 others were injured on Thursday in four separate attacks against security installations in the governorate. Casualties included both civilians and security personnel.

Egypt's most active militant group, Ansar Bayt al-Maqdis, claimed responsibility for Thursday's deadly attacks. The group changed its name to Sinai Province after pledging allegiance to Islamic State fighters in Syria and Iraq last November.

Egypt's Supreme Council of the Armed Forces announced on Saturday a presidential decree establishing a unified army command east of the Suez Canal "to fight terrorism", in response to the attack.