Another leading figure in the Muslim Brotherhood figure has been arrested.
State media said Freedom and Justice Party secretary-general Mohammed al-Beltagi is accused of inciting violence.
Prosecutors ordered the arrest of Mr Beltagi on 10 July after the ousting of former President Mohammed Morsi by the Army on 3 July.
The BBC reports much of the Brotherhood's senior leadership is already under arrest, including Mohamed Badie and his deputy Khairat al-Shater.
The interim government has said that the Brotherhood is a terrorist organisation.
