An Egyptian court sentenced an icon of the 2011 uprising to five years in prison on Monday, in the latest sign of authorities' determination to stifle dissent despite promises by the president to release "wrongly jailed youths."

The verdict in the retrial of well-known activist Alaa Abdel-Fattah reduced an earlier 15-year prison sentence for organizing an unauthorized protest and allegedly assaulting a police officer. But the ruling was condemned by defense lawyers and supporters who said he should have been set free.

The retrial began in October and involved 25 defendants, five of whom are fugitives. Beside Abdel-Fattah, only one other defendant, Ahmed Adel-Rahman, received a five-year prison sentence. The rest were sentenced to three years.

Judge Hassan Farid also ruled that Abdel-Fattah, Abdel-Rahman and the rest of the defendants be placed under police surveillance for a period similar to their prison terms after their release, requiring them to report daily to the police.

The courtroom erupted after the verdict, with relatives and friends in the gallery shouting: "Down with oppression!" One man collapsed as Abdel-Fattah's family and friends wept and screamed: "Down with military rule!" Police ultimately ordered everyone to clear the courtroom.

About 100 relatives, friends and activists, some tearful and angry, waited outside the gate of the police academy where the trial was held, hoping for a glimpse of their loved ones in the police truck taking them back to prison.

Defense lawyer Mohammed Abdel-Aziz decried the verdict as "harsh and oppressive."

The court "didn't take into consideration any of the evidence that showed the defendants' innocence," he said.

Another rights lawyer, Taher Abou el-Nasr, said: "Regrettably, the verdict was expected. We no longer expect acquittals."

Lawyers said they will appeal the ruling to Egypt's Court of Cassation, the country's highest appeals court.

In a brief address before he delivered the verdict, Judge Farid insisted the ruling was "free of any interference or caprices." Egyptian officials insist the judiciary is independent and does not rule based on political considerations.

An outspoken blogger, Abdel-Fattah has been in and out of prison in the years since the 2011 ouster of autocrat Hosni Mubarak. He campaigned against military trials for civilians during the nearly 17 months that generals held power following Mubarak's resignation. He also opposed Islamist President Mohammed Morsi, whom the military overthrew in 2013.

The charges against him stem largely from a law prohibiting protests without government permission, a measure adopted a few months after Morsi's July 2013 overthrow. Activists and rights groups have criticized the law.

"I know of no other country in the world that jails young people for three or five years for taking part in peaceful protests," said Khaled Dawoud, spokesman for the Dostour party, of which two members were sentenced to three years in prison on Monday.

Abdel-Fattah was accused of inciting an "unauthorized" demonstration on Nov. 26, 2013. That demonstration was called to protest a clause allowing military trials for civilians in the draft of a new constitution, which was later adopted in a referendum.

Mona Seif, Abdel-Fattah's sister and one of the organizers of the Nov. 26 protest, said he attended the demonstration but denied he had organized it, saying it was called for by a group that campaigns against military trials for civilians.

Police violently dispersed the protest on the grounds that organizers had no permit. More than a dozen women, including Seif, were detained by police and dropped off in the middle of the desert outside of Cairo later that night.

Abdel-Fattah previously said his trial was a farce. He went on a hunger strike but has been drinking juice the last week.

The ruling, which also dropped an earlier robbery charge, comes a day after Egyptian President Abdel-Fattah el-Sissi promised to release youths wrongly arrested. He said the coming days would see the release of a "first batch."

The new measure is not expected to affect those on trial like Abdel-Fattah, but it could lead to the release of youths who have been rounded up at demonstrations but not yet charged. Rights groups say there are more than 20,000 people behind bars now in Egypt, most of them Islamists rounded up after Morsi's ouster.