The discovery of a dummy bomb at Alexandria University on Saturday sparked panic on the campus.
Explosives experts examined the device, found near the faculty of engineering, and told Al-Ahram Arabic website that it was a fake and did not contain actual explosives.
Director of Security in Alexandria Nasser El-Abd told Al-Ahram that the device was a prank.
Egypt witnessed two explosions in the past week. On Tuesday, a huge bomb rocked the security directorate building in the northern city of Mansoura, killing 16 people and injuring more than 135, while on Thursday a smaller explosion in eastern Cairo near a bus injured five people.
Ansar Bayt Al-Maqadis, a Sinai-based militant group, claimed responsibility for the Manoura bombing, but Egypt's interim government has blamed the Muslim Brotherhood for the attack, despite the Brotherhood denying their involvement.
No group has yet claimed responsibility for the bomb in Cairo, which according to explosives experts was on the road not on the bus.
The explosives experts have also managed to defuse another bomb found near the Nasr City explosion site, which reportedly was targeting the police rushing to the scene after the explosion.