Two prominent Egyptian secular activists will stand trial on Sunday for allegedly taking part in a violent and unauthorised protest under a disputed new law, judicial sources said.
The pair, Ahmed Maher and Ahmed Douma, were arrested after Maher's supporters allegedly scuffled with policemen outside a Cairo court, as Maher handed himself in for questioning on suspicion he had organised an illegal protest.
A third activist, Mohammed Adel, would be tried in absentia, the judicial sources said on Thursday.
The activists are charged with assaulting police officers at an illegal protest.
Both Maher and Douma were leading dissidents under toppled dictator Hosni Mubarak, and supported the military's overthrow of Islamist president Mohamed Morsi in July.
But the passage of a law on November 24 that bans all but police-authorised protests has angered secular activists who had viewed the military-installed government as a lesser evil compared with Morsi.
Secular activists and rights groups see the arrests as widening of a crackdown on protests by the authorities, which until now have been targeting Islamist supporters of Morsi.
The crackdown against Morsi's supporters has killed more than 1,000 people in recent months and thousands more, mostly Islamists, have been arrested.
The trial of Maher and the two other activists in a misdemeanour court will be the first under the new protest law, which sparked criticism from within the interim government and internationally.
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Police rounded up dozens of activists who violated the law in a protest outside the senate last week, including some of the country's most prominent women activists.
All of them have since been released, but a leading blogger, Alaa Abdel Fattah, remains in detention after police arrested him days later in connection with the protest.
He was arrested at his home in western Cairo, said his wife, Manal Hassan, who tweeted that she had been "beaten" during the operation by security forces.
The protest law requires organisers to seek authorisation three days ahead of any planned demonstration. The request can be denied if the protest is deemed a threat to national security.
Demonstrations at places of worship, or starting from them, are banned outright.
Activists say the ban is hypocritical as the army justified the ouster of Morsi as a response to mass demonstrations across the country against his turbulent single year in power.
Police have since enforced the law, at times bloodily, and the government says it has no intention to amend it for now.
Days after it went into force, an engineering student was shot dead as police confronted Islamist student demonstrators at Cairo University.
The interior ministry and prosecutors allege the student was killed by his colleagues, further infuriating student activists.