An Egyptian police officer was killed late Friday when an explosion rocked a busy district in central Cairo, state news agency MENA reported.
A bomb targeting a traffic checkpoint was detonated in the Lebanon Square in western Mohandessin district of Giza, killing a police officer from the Giza traffic department and injuring another, the security forces said, Xinhua reported.
Witnesses said several attackers riding a motorbike threw the bomb from a nearby bridge above the checkpoint.
An investigation has been launched to search for the attackers and more possible devices.
No one has yet claimed responsibility for the attack. But a Sinai-based Jihadist group Ansar Beit Al-Maqdis, closely related to al-Qaida, had claimed responsibility for most of similar attacks.
Violence and militant attacks targeting security forces and their installations have escalated across Egypt after the ouster of Islamist President Mohamed Morsi last July. Hundreds of soldiers and policemen have been killed, especially in the lawless northern Sinai Peninsula.
In recent months militant assaults have been creeping into the capital Cairo and other Nile Delta cities.