Several thousand protesters have started gathering at Tahrir Square for a mass protest organised by Salafist forces scheduled to start after Friday's noon prayer to demand that Egypt's new constitution be based on the "rules of Islamic Sharia."
Many demonstrators have arrived in chartered buses from provincial areas.
On Thursday night, protesters built a huge stage inside the square with banners demanding the enforcement of the "law of God".
"We promise the prophet of God that we will sacrifice ourselves for the sharia of God," read one of the banners.
The protest, which was called for by a number of Salafist groups including Al-Gamaa Islamyia and the Salafist front, also calls for the dismissal of the Prosecutor General.,
Meanwhile, Egypt's most influential Islamist groups the Muslim Brotherhood and the Salafist Al-Nour party announced that they will not participate in the protest.
On 2 November, a preliminary protest was held in Tahrir by thousands of Islamist youth to prepare for Friday's protest.