Egyptian prosecutors ordered on Thursday the arrest of a number of senior members of the Muslim Brotherhood hours after the army ousted elected president Mohamed Morsi.
These include the Brotherhood Supreme Guide Mohamed Badie and his deputy Khairat El-Shater.
Security authorities are continuing their efforts to arrest Brotherhood members on charges of inciting violence and disturbing general security and peace, state news agency MENA reported.
Late on Wednesday, Saad El-Katatni, leader of the Muslim Brotherhood's Freedom and Justice Party (FJP), along with Rashad Bayoumi, the deputy head of the Islamist movement were detained, security officials said.
They are being held in Tora Prison, located on the outskirts of Cairo, the same prison where ousted president Hosni Mubarak and his sons are detained, MENA reported.
Members of the Brotherhood are accused of murdering protesters outside the group's headquarters in the Cairo suburb of Moqattam on 30 June, when millions of Egyptians flooded the streets to call for Morsi's ouster.
The group allegedly hired and armed some 250 members and snipers at its head office to kill protesters outside, a judicial source said.
At least eight were killed when those inside fired at youth hurling petrol bombs and stones at the building.
Mohamed Morsi, whom the group presented as its second choice candidate in last years' presidential elections, was ousted on Wednesday by the Egyptian army. The head of Egypt's top court was sworn in as the caretaker head of state on Thursday.
The toppled president himself was also being held by the military-led authorities, a Brotherhood spokesman told Reuters on Wednesday night. A security official said he was being held at a military intelligence facility.