The Christians were chanting slogans against Islamist President Mohammed Morsi, just as several thousand did earlier during the funeral service nearby in the Coptic Orthodox cathedral in Cairo.

NPR: Christian Mourners, Mob, Police Clash In Egypt

Several liberal and secular members of the assembly had already withdrawn because of the criticism, as well as the Egyptian Coptic Orthodox Church and Al-Azhar Institution, one of the most influential Islamic entities.

CNN: Row over Egypt's new constitution reflects wider tensions

The General Bishop of the Coptic Orthodox Church in Britain, Bishop Angaelos, said that he had discussed the threats with fellow bishops across Europe and that precautions taken after earlier attacks had been heightened.

BBC: Coptic churches in Europe report attack threats