Egyptian police Monday arrested the head of the defence team for 21 young Islamist women and girls jailed last week in the northern city of Alexandria, local media reported.
Lawyer Ahmed al-Hamrawi was arrested with five others on charges of inciting violence, a senior police official told independent daily Al-Masry Al-Youm, dpa reported.
General Nasser al-Abd told the newspaper that the arrest was not related to the case of the 21 women and girls, who were convicted on charges of illegal assembly, destroying property and carrying weapons at a protest they held in support of deposed president Mohammed Morsi.
The sentences handed down to the protesters, whose lawyers said their action was entirely peaceful, triggered strikes in the country.
Seven secondary school students were sent to juvenile homes until they turn 18, while the 14 adult defendants - mainly university students - were each jailed for 11 years.
The Alexandria Appeals Court is expected to hear an appeal against the verdict on Saturday.
Presidential adviser Sekina Fouad has said that interim president Adly Mansour will pardon them once appeals in the case have been exhausted.
Meanwhile, police clashed with protesters outside an Alexandria court where a hearing was underway in the retrial of two policemen accused of beating to death a 28-year-old in June 2010.
Security forces used tear gas and water cannon to break up the protest outside the court building, state-run newspaper Al-Ahram reported online.
The death of Khaled Said was one of the catalysts of the revolution that toppled president Hosny Mubarak, as pictures of his disfigured face were widely circulated on social media.
A Facebook page called "We are all Khaled Said" became one of the country's most popular, channeling widespread anger at a police force that was seen as brutal, corrupt and unaccountable.
The page - secretly administered by Google marketing manager Waled Ghoneim - was one of the first to call for the demonstrations on January 25, 2011, National Police Day, which later grew into a popular uprising.
Two detectives were found guilty of using excessive force against Said and sentenced to seven years in prison in 2011, but the verdict was overturned on appeal.