Cairo: A recent court ruling upholding prison terms against three prominent Egyptian activists has galvanised several pro-democracy groups into launching a campaign pushing for the release of dozens of protesters detained in a security crackdown in recent months.

On Monday, the Cairo Appeals Court upheld the three-year-prison sentence each given to Ahmad Maher, Mohammad Adel and Ahmad Douma for violating a law banning street protests without prior permission from police.

They were also accused of attacking policemen outside a Cairo court and damaging public and private property.

The three had mobilised a 2011 uprising that unseated Egypt’s long-standing president Hosni Mubarak. Their April 6 Movement has vowed massive protests to demand their release and repeal the controversial law.

“Imprisonment rulings passed against the three activists and others threaten their future although they were the ones who sacrificed themselves for the revolution in pursuit of freedom,” said Hala Shukrallah, the head of the liberal Al Destour Party.

She vowed protests against the law restricting public demonstrations. “This law illogically makes peaceful protests equal to the violent protests,” Hala told a press conference on Tuesday.

She added that a list of detained activists is being compiled and caretaker President Adly Mansour will be asked to pardon them.

Scores of secular democracy advocates this week staged a protest against the law near the presidential palace in Cairo.

In November, Mansour, a former judge, ratified a draft bill authorising police to ban or approve public demonstrations, drawing wide local and foreign condemnation. Critics say the law heavily restricts freedom of expression and is aimed at stifling political dissent.

Authorities say the law is necessary for curbing violent protests, mainly blamed on backers of Islamist president Mohammad Mursi, who was deposed by the army in July last year following enormous street protests against his rule.

Around 1,079 activists have been arrested since early this year, allegedly for violating the ban on protests, according to pro-democracy groups.

“It has become clear since this law went into effect that it is hard to enforce,” said Hussam Moanes, the spokesman for the Popular Current, an opposition coalition led by presidential contender Hamdeen Sabahi.

“This law has failed to deter terrorist attacks or stop violence in the universities,” Moanes added.

Egypt has seen a string of attacks since Mursi’s toppling. Students backing Mursi have, meanwhile, held anti-government protests in recent months, demanding his reinstatement. On several occasions, protestors have violently clashed with security forces.

The military-backed government has blamed Mursi’s Muslim Brotherhood for the violence and branded it as a terrorist organisation.