Troops continued to guard the entrances to Tahrir Square on Monday morning after security forces dispersed anti-army protesters the day before.
There are tanks and barbed wire at the entrances to the square and in the surrounding streets, state news agency MENA reported.
On Sunday, security forces fired teargas to disperse hundreds of Islamist student protesters gathering in Tahrir to decry last week’s killing of a colleague by police at Cairo University.
It was the first time Islamists had occupied the highly symbolic square, which has become mainly a venue for secular protests, since the ouster of Islamist president Mohamed Morsi.
Armoured vehicles moved in to drive the demonstrators away, forcing them to take refuge in side streets.
Two months ago, a number of Morsi supporters briefly entered Tahrir, the epicentre of the 2011 uprising that toppled Hosni Mubarak, before clashes broke out with opponents who drove them away.
The square, along with other major protest venues, has been sealed off on major protest days since Morsi’s ouster by the army in July after millions protested his year-long reign.
Al Ahram