CAIRO, Egypt -- An appeals court on Monday upheld the convictions and three-year prison sentences handed down to three of Egypt's most prominent political activists, a ruling that is likely to revive opposition to a draconian protest law they were accused of violating.
It is also certain to deepen the rift between the current military-backed government and Egypt's liberal and secular pro-democracy campaigners, many of whom participated in the 2011 popular uprising against Hosni Mubarak.
The ongoing campaign against dissent and pro-democracy activists has been overshadowed by a much larger crackdown against the Muslim Brotherhood group and other Islamists. That push has led to the death of hundreds and the jailing of at least 16,000 people since the July ouster of President Mohammed Morsi.
The three -- Ahmed Maher, Mohammed Adel and Ahmed Douma -- were charged with breaking a law issued last November that bans all political gatherings and protests held without prior permission from the police.
The verdict swiftly drew condemnation from international rights groups.
The ruling "tightens the vice on freedom of expression and assembly and is yet another sign of Egypt's growing climate of intolerance toward any legitimate criticism of the authorities," said Hassiba Hadj Sahraoui, deputy Middle East and North Africa director at Amnesty International.
She said the three never should have been put on trial and called for their release.
Sarah Leah Whitson, director of the Middle East and North Africa in the New York-based Human Rights Watch, said the verdict "is one more nail in the coffin for Egypt's revolution."
Senior leftist politician and presidential hopeful Hamdeen Sabahi called on interim President Adly Mansour, installed by the military in July, to pardon the three.
"It is unbecoming for Egypt ... to jail those among its youth who revolted because of an oppressive law," he wrote on his Twitter account.
The ruling sparked a storm of anger on social media networks. Dozens of activists called for a sit-in outside the presidential palace in the Cairo district of Heliopolis. Douma's wife wrote on her Twitter account that she was headed there.
By late afternoon, several activists wrote on their Twitter account that their sit-in has started, defying the law on protests that requires a permit in advance. "We began the sit-in ... girls and women demanding freedom for their brothers, sons and loved ones," wrote one activist, Mona Seif.
The three young activists were among the founders of the April 6 movement. The group first gained nationwide attention when its activists openly challenged the Mubarak regime and its brutal police force with calls for a general strike in 2006. In the industrial city of Mahalla in the Nile Delta, a giant poster of Mubarak was ripped off and trampled on by protesters, a first at the time.
It was at the forefront of the 18-day uprising against Mubarak in 2011. It later joined the opposition against the generals who took over the reins of power for nearly 17 months after Mubarak's ouster. When the movement marked its sixth anniversary on Sunday, security forces sealed off Cairo's central Tahrir square, birthplace of the 2011 uprising, to prevent followers from celebrating there.
After Morsi's June 2012 election, April 6 initially supported him as the first democratically chosen president. But it soon became disillusioned with the Islamist leader's perceived attempts to concentrate power in his Muslim Brotherhood. April 6 supported Morsi's removal by the military last July, after days of protests by millions of Egyptians against his rule.
But again, April 6 shifted its stance to denounce what it describes as the curtailment of freedoms and the heavy handedness of the police under the current military-backed government.
The predominantly pro-military media has cast the April 6 movement as a treasonous organization with foreign links.
The three were accused of violating a controversial new law on holding street protests and were sentenced each to three years in prison in December. Maher was initially accused of taking part in an illegal protest in November.
He later surrendered to authorities, but clashes between his supporters and security forces outside the police station prompted prosecutors to amend the charges to assaulting police officers and organizing an illegal protest.
Douma and Adel were later added to the case.
Douma suffers from stomach ulcer and has complained in past court hearings that he was not being properly treated in jail. He appeared to have lost a great deal of weight when he appeared in court on April 1 for another trial.
The government depicts the protest law as aimed at bringing order to the streets in the face of months of continued demonstrations by Islamist supporters of Morsi. There has been no public sign of the law being applied to street gatherings by supporters of the military.
The court also ruled on Monday that each of the three would be fined 50,000 Egyptian pounds (about $7,140).
One of the defence lawyers, Gamal Eid called the verdict "oppressive" on his Twitter account just after the ruling was read.
Another defence lawyer, Ahmed Seif al-Islam, said he planned to appeal to a higher court, and if that fails turn to the African Court on Human and People's Rights.
Ragia Omran, a prominent rights lawyer, called for pressure on Mansour to rescind the law. The interim president currently holds legislative powers since parliament was dissolved.
"He can do this," she said. "This law has proven ridiculous, achieved nothing and will give rise to a new generation (of revolutionaries) that will come out to fight the regime."