The Muslim Brotherhood's former supreme guide Mahdi Akef has been arrested along with four of his guards, security sources say.
Egypt prosecutors ordered on Thursday the arrest of a number of senior Muslim Brotherhood members hours after the army removed Mohamed Morsi from his post as president.
These leading figures include the Brotherhood's Supreme Guide Mohamed Badie and his deputy Khairat El-Shater.
Late on Wednesday, Saad El-Katatni, leader of the Muslim Brotherhood's Freedom and Justice Party (FJP), and Rashad Bayoumi, the Islamist movement's deputy head, were detained, security officials said.
They are being held in Tora Prison, which, located on the outskirts of Cairo, is the same prison where ousted president Hosni Mubarak and his sons are detained, state news agency MENA reported.
Security authorities are continuing their efforts to arrest Brotherhood members on charges of inciting violence and disturbing general security and peace, MENA reported.