Egyptian police fired live rounds in the air to disperse about 1,000 anti-government protesters in central Cairo on Saturday, a Reuters witness said, amid fears of violence on the anniversary of the 2011 revolt that ousted autocrat Hosni Mubarak.
The witness said police also fired tear gas and birdshot at a crowd of secular-minded liberal activists attempting to march toward Cairo's Tahrir Square to protest against the military-backed interim government.
A bomb exploded near a police academy in Cairo on Saturday, wounding one person, security sources said.
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.
Militants have stepped up attacks since the army toppled President Mohamed Mursi. Hundreds of security forces have been killed.
Mursi's overthrow plunged Egypt into political turmoil which has hit investment and tourism hard.
More violence is expected on Saturday, when rival political factions gather to mark the anniversary of Mubarak's downfall.