Egypt's interim president Adly Mansour has said there will be presidential elections before the next round of parliamentary polls, reversing the order of an earlier roadmap. The announcement comes after at least 49 people were killed in protests.
A bomb exploded near a police academy in Cairo on Saturday, wounding one person, security sources told Reuters.
The explosion, which occurred on the third anniversary of the uprising that toppled autocrat Hosni Mubarak, came a day after a wave of bomb attacks targeting police killed six people and raised fears that an Islamic insurgency is gaining momentum.
Islamist militants have stepped up attacks since the army toppled President Mohamed Morsi of the Muslim Brotherhood in July. Hundreds of security forces have been killed.
Egypt is on high alert after a wave of bomb attacks targeting police hit Cairo on Friday, killing at least 18 people.
It comes on the eve of the third anniversary of the uprising that toppled former president Hosni Mubarak, raising fears that an Islamist insurgency is gaining pace in Egypt.
Authorities have been bracing for more violence as rival political groups are expected to turn out, including supporters of army chief General Abdel Fattah al-Sisi, members of the Muslim Brotherhood and liberals.
The 2011 revolt raised hopes of a stable democracy in the Arab world's largest nation. Instead, relentless political turmoil has hit investment and tourism hard in Egypt.