Nine others were reportedly injured and more than a hundred arrested in clashes between police and the protesters who had gathered at Tahrir Square in the capital, Cairo, on Saturday.
Armored vehicles and security forces blocked the entrance to Tahrir Square in the evening, witnesses said.
A number of people also staged a protest rally against the court verdict in the city of Suez on the same day.
Earlier in the day, an Egyptian court dismissed a murder charge against Mubarak in connection with the killing of hundreds of protesters during the 2011 uprising that ended his decades-long rule.
The court also acquitted Mubarak of a corruption charge, but the toppled president will remain in prison as he is serving a three-year sentence at a military hospital for embezzling public funds.
Seven of Mubarak’s commanders, including former Interior Minister Habib al-Adly, were also exonerated in connection with the deaths of some 800 demonstrators killed during the uprising.
Corruption charges against Mubarak’s sons, Alaa and Gamal, were also dropped.