Article Photos: Egypt army chief warns state could collapse 27/47

An Egyptian protester part of the Black Bloc, clashes with riot police, not seen, near Tahrir Square, Cairo, Egypt, Monday, Jan. 28, 2013. An unpredictable new element has entered Egyptâs wave of political unrest, a mysterious group of black-masked young men calling themselves the Black Bloc. They present themselves as the defenders of protesters against the rule of President Mohammed Morsi, but Islamists have used them to depict the opposition as a violent force wrecking the nation. (AP Photo/Khalil Hamra)