Egypt has detained 22 women members of the Muslim Brotherhood, a security official said on Friday, fuelling tensions days before deposed President Mohamed Morsi and 14 other leaders of the Islamist group go on trial.
Security forces have arrested thousands of Islamists since the army toppled Morsi on July 3 and promised a roadmap would lead to free and fair elections. But they rarely detain women Islamists, especially in such big numbers.
Nasser al-Abd, a senior security official in Egypt's second city Alexandria, said the charges against the women include using force to disrupt traffic during protests, membership of in outlawed group and distributing illegal leaflets.
A lawyer representing the suspects said they were aged between 15 and 25. They were detained on Thursday morning.
Islamists and human rights groups accuse the army of staging a coup and returning Egypt to the days of Hosni Mubarak, who ruled Egypt with an iron fist for three decades before he was toppled in a popular uprising in 2011.
Hundreds of Islamists have been killed and the Brotherhood's leaders have been imprisoned. Egypt has also declared a state of emergency and imposed a night-time curfew.
Morsi's supporters have called for daily protests starting on Friday until the ousted president stands trial on Monday.
The trial is likely to deepen hostility between the Brotherhood and the army-backed interim government as it struggles to restore stability in the most populous Arab state.
The Brotherhood and its allies have urged crowds to move on Monday to a police institute near Cairo's notorious Tora prison, where the trial is expected to take place.
The charges relate to the deaths of about a dozen people in clashes outside the presidential palace in December after Morsi enraged his opponents with a decree expanding his powers.
Morsi has been held in a secret location since his overthrow. In that time Islamist militants have staged almost daily attacks against security forces in the Sinai Peninsula.
Supporters and opponents of the Brotherhood have often clashed in the streets.
A court order has banned the Brotherhood, Egypt's oldest and best organized Islamist movement, and seized its funds.
The Brotherhood denies any links with violent activity.
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