Five protesters were arrested following clashes between anti-government protesters and security forces in front of the Muslim Brotherhood headquarters in Zagazig, the capital of Sharqiya in Egypt's Nile Delta on Friday.
The liberal Constitution Party confirmed that one of its members, Ibrahim El-Refaie, was among those arrested and called for a demonstration in front of the Zagazig security directorate Saturday to demand their release.
Dozens of protesters clashed with security forces guarding the headquarters of the Islamist group, whose political arm, the Freedom and Justice Party, fielded President Mohamed Morsi in the elections.
Protesters reportedly threw rocks at police lines and set fire to a number of trees after the five were arrested.
Friday's protest in Zagazig was part of a nationwide call by Egypt's opposition umbrella group, the National Salvation Front, to demand the removal of the current Morsi-appointed prosecutor-general.