Egyptian prosecutors on Tuesday remanded 388 pro-democracy activists in custody for 15 days pending investigation into their alleged role in Sunday\'s clashes with security forces. The 388 activists were detained in Cairo\'s Ramses Square and in Giza\'s Dokki district. Prosecutors accused the defendants of \"damaging public and private property\" and \"assaulting security forces.\" The detainees, for their part, have denied all charges. At least 54 pro-democracy protesters were killed by security forces on Sunday. Demonstrators had staged rallies and marches countrywide to denounce the army\'s July 3 ouster of President Mohamed Morsi, Egypt\'s first-ever freely elected leader. Most deaths occurred in capital Cairo and the adjacent Giza province. In a statement, the Muslim Brotherhood\'s Freedom and Justice Party – of which Morsi had served as chairman before assuming the presidency in June of last year – demanded an international investigation into the killings. The party held Egyptian military chief Abdel-Fattah al-Sisi and Interior Minister Mohamed Ibrahim responsible for the \"deliberate killing of peaceful protesters.\"