Police fired tear gas as more than two thousand students backing ousted Islamist president Mohamed Morsi entered Cairo's Tahrir Square to demonstrate against July's military "coup," an AFP reporter said. Sunday's demonstration was the first Islamist protest in the Egyptian capital's iconic square -- the epicentre of the 2011 revolt against long-ruling president Hosni Mubarak -- since Morsi's ouster by the army on July 3.