Earlier today, a medical source said an army officer and two soldiers were wounded when unidentified gunmen fired an RPG at an army vehicle in al-Kawthar area at the time of iftar (fast-breaking).
Eyewitnesses said the vehicle was totally destroyed in the attack.
Gunmen also attacked the Sheikh Zuweid police station and opened fire on four security checkpoints around the city.
Flames of smoke were seen rising from the area.
No group has yet claimed responsibility for the attack.
On Thursday, two soldiers were killed and four injured when gunmen stormed a border guard headquarters in the northern Sinai Peninsula.
At least 35 people, both civilians and security personnel, have been killed in a spate of militant attacks in Sinai since July 5, two days after the military ousted Mohamed Morsi, Egypt's first democratically elected president.