A woman protester was shot dead in central Cairo on Saturday, security sources said, one day before the anniversary of the popular uprising that ousted autocrat Hosni Mubarak in 2011.
Shaimaa al-Sabbagh of the Socialist Popular Alliance Party was killed when police were dispersing a protest in downtown Cairo.
On Friday, an Egyptian student was killed during clashes between protesters and residents in the Mediterranean port city of Alexandria.
A security crackdown mounted after the army toppled Egypt’s first freely elected civilian president Mohamed Morsi of the Muslim Brotherhood in 2013 had virtually ended street demonstrations.
But several protests erupted this week in Cairo and Egypt's second city Alexandria in the run-up to the anniversary of the 18-day revolt that ended 30 years of iron-fisted rule under Mubarak.
The security sources said the protester was shot dead with birdshot near Tahrir Square, the symbolic heart of the 2011 revolt. They did not elaborate.
Human rights activists say a law restricting protests and other security legislation have rolled back freedoms won in the 2011 uprising. The government says it is committed to democracy.
As army chief, Abdel Fattah el-Sissi toppled Morsi after mass protests against his rule. Sissi went on to become Egypt's elected president.
Islamists and liberal activists, including many who supported Morsi's removal, have been jailed, with many facing trial for taking part in small protests.
Sissi said this week Egyptians had the right to protest but cautioned that demonstrating could harm the economy.