At least 2,000 Muslim Brotherhood leaders and activists have been arrested and the movement banned since August, when its strongholds were stormed and hundreds were killed.Meanwhile, security forces used tear gas and fired into the air as hundreds of pro-Morsi demonstrators tried to converge on the square from different directions.
There were running skirmishes in many parts of the city. The Morsi supporters also clashed in some areas with residents who strongly supported the army.
Dozens of people have been killed and many more hurt in Egypt in clashes between police and supporters of the deposed Islamist President Mohammed Morsi.
In Cairo, tens of thousands of Mr Morsi’s opponents were in Tahrir Square celebrating the 40th anniversary of the 1973 Arab-Israeli war, and expressing their support for the army.
The crowds cheered as jets flew overhead in formation, as part of a display of military hardware by the government.
The street battles raged for hours, with small fires burning and black smoke rising.
As night fell the numbers of deaths reached double figures, but these protests were far less bloody than previous clashes between the two sides in Egypt’s ongoing crisis.
At least 2,000 Muslim Brotherhood leaders and activists have been arrested and the movement banned since August, when its strongholds were stormed and hundreds were killed.