A march from Fatah Mosque led by former presidential candidate Khaled Ali arrived on Friday in Cairo's Tahrir Square to take part in the "Dream of the Martyr" million-man demonstration, al-Masry al-Youm newspaper reported.
Hundreds have been gathering in Tahrir since Friday morning to revoke the constitutional declaration President Mohamed Mursi decreed last week.
The demands of the protesters include reshuffling the constituent assembly, ensuring the independence of the judiciary, avenging the martyrs, cleansing the ministry of interior and sacking Prime Minister Hisham Kandil's cabinet.
Protesters held banners saying "An Egyptian constitution for all Egyptians" and "No to the constitution of the Brotherhood".
They chanted slogans such as "Dictator, dictator, it is your turn, Mursi" and "Down with the Brotherhood".