Egypt crisis: Tight security for Tahrir Square rally

Supporters of the military-backed government in Egypt have gathered for a huge rally in Cairo's Tahrir Square.

Demonstrations held by opponents of the government were broken up by police using tear gas, and several protesters have been killed during clashes in Cairo and other cities.

Tension surrounding the third anniversary of the uprising lead to violence on Friday, in which at least 18 people died.

The BBC's Sally Nabil, reporting from Tahrir Square, says security surrounding the pro-government rally is extremely tight.