Egyptian police have used tear gas to disperse protesters angry that charges against ex-President Hosni Mubarak over killings during the uprising three years ago have been dropped.
About 2,000 people massed in Cairo's Tahrir Square, the birthplace of the 2011 revolution. One person was reported killed in the clashes, the BBC reported.
Mubarak was originally sentenced to life in jail then cleared in a retrial.
In a TV interview after the ruling, Mubarak said he did "nothing wrong".
The former president, 86, was serving a separate three-year sentence for embezzlement of public funds.
He was currently being held in a military hospital, and was expected to serve at least a few more months of this sentence.
Mubarak, his former Interior Minister Habib al-Adly and six others had been convicted of conspiracy to kill and were sentenced to life in prison in June 2012, but a retrial was ordered last year on a technicality.
In all, some 800 people are thought to have been killed as security forces battled protesters in the weeks before Mubarak resigned on 11 February 2011.