SECURITY forces fired tear gas and clashed with several thousand protesters in Cairo’s Tahrir Square in the third straight day of violence that has killed at least 33 people and has turned into the most sustained challenge yet to the rule of Egypt’s military.

Tens of thousands of Egyptians waved flags and shouted slogans today in Cairo’s central Tahrir Square, demanding that Hosni Mubarak and his family be put on trial over allegations of corruption.