Egypt prosecutors extended the detentions of Salafist leader Hazem Salah Abu-Ismail and Muslim Brotherhood leaders Helmi El-Gazzar, Abdel-Moneim Abdel-Maqsoud, and former MP Mohamed El-Omda for another 15 days on Sunday, pending investigation into charges of inciting the murder of anti-Morsi protesters.
The Islamist figures were arrested following the ouster of former president Mohamed Morsi, who hails from the Muslim Brotherhood.
The prosecution charged the four leaders with inciting the violence that led to nine protester deaths during clashes between Morsi supporters and opponents near Giza's Cairo University on 30 June.
Dozens of Islamist leaders and hundreds of Muslim Brotherhood members have been arrested since Morsi's ouster. A common charge cited in these arrests is incitement of violence during past clashes.