Supporters of ousted president Mohamed Morsi have called for demonstrations on Friday after security forces raided a pro-Morsi area on the outskirts of Cairo.
The National Alliance to Support Legitimacy, an Islamist grouping led by the Muslim Brotherhood, said the protests would continue for a week under the slogan "Youth are pillar of the revolution" to mark the start of the new academic year.
Security forces raided the Islamist bastion of Kerdasa on Thursday to round up suspects accused of killing 11 policemen in the city last month.
A senior security officer was shot dead and at least 10 policemen injured during the operation
The interior ministry said the raid would flush terrorists from the area.
It was the second such raid this week. On Monday, security forces rolled into Dalja in Upper Egypt's Minya governorate, which had been partially controlled by Islamist hardliners accused of burning churches and terrorising local Christians.
Egypt's interim government last week extended a state of emergency, in force since mid-August, by another two months amid continued political unrest.
On Thursday, a night-time curfew imposed in Cairo and 13 governorates was shortened to between 12am and 5am, except on Fridays when it will begin at 7pm.
Islamists have held regular protests since Morsi's ouster on 3 July, but the numbers have sharply diminished in recent weeks amid a sustained clampdown by security forces.
Hundreds of people were killed when police cleared two pro-Morsi protest camps in Cairo and Giza on 14 August, sparking the largest flare-up of street violence in Egypt's modern history.