'Calm atmosphere' in Tahrir Square Mubarak protest

Tens of thousands of Egyptians are taking part in a "day of departure" rally to try to oust President Hosni Mubarak.

The BBC's Rupert Wingfield-Hayes in Tahrir Square reports that after days of violence and tension the demonstrations have assumed a friendly and calm atmosphere.

Mr Mubarak is under increasing pressure to resign, with the US now calling for an immediate transition of power. He says such a move would leave Egypt in chaos, but has admitted he is "fed up" with being in power.