Army retreats from clashes in Cairo's Tahrir Square

Anti-government protesters in Egypt have fought back against supporters of President Hosni Mubarak, pushing them out of some streets in central Cairo which they controlled.

Stones were thrown on both sides, and some gunshots were fired.

The army, which was trying to separate the two sides, appears to have failed to control the crowds.

The BBC's Ian Pannell was prevented from reporting in Cairo's Tahrir Square by pro-Mubarak supporters angry at media coverage.