Five people were wounded by a bomb close to a bus in the Egyptian capital, Cairo on Thursday.
The bomb was on a pedestrian island in the district of Nasr City and exploded as the bus went by.
A security source has told the BBC that a second bomb planted in an advertising board close to the scene, had since been detonated by explosive experts.
On Tuesday, 16 people were killed and more than 100 others wounded by a car bomb attack at security building in the northern city of Mansoura.
Defence Minister General Abdul Fattah al-Sisi said Egypt would remain resilient against terrorism.
"Don't let these cruel terrorist incidents affect you or your morale," he said at a military ceremony in Cairo.
The Muslim Brotherhood was declared a terrorist organisation by the interim government on Wednesday.
