An Egyptian security official says three explosions have targeted a military and police convoy in volatile northern Sinai, wounding four troops.

The official says Friday's explosions, one of which was from a roadside bomb, hit near the town of Sheikh Zuweid, close to the border with the Gaza Strip.

The official spoke on condition of anonymity in line with regulations.

The northern part of the Sinai Peninsula has seen a rise in attacks and suicide bombings by suspected Islamic and al-Qaida-inspired militants, especially after the Islamist President Mohammed Morsi was ousted in a popularly-backed coup in July.

Egypt's interim, military-backed government has designated Morsi's group, the Muslim Brotherhood, as a terrorist organization and accuses it of ties to a known al-Qaida-inspired group that has claimed many of the Sinai attacks.