Egypt: fourth night of protests in Tahrir Square – in pictures

Hundreds of thousands of Egyptians occupy Cairo's Tahrir Square for a fourth night of protests against the military government Photograph: Amr Abdallah Dalsh/Reuters Protesters chant slogans against Field Marshal Mohamed Hussein Tantawi Photograph: Mohamed Abd El Ghany/Reuters Protesters run from teargas thrown at them by police Photograph: Asmaa Waguih/Reuters A protester runs as another throws a teargas canister at police Photograph: Peter Macdiarmid/Getty Images A man suffering from the effects of teargas lies in a makeshift medical centre in Tahrir Square Photograph: Peter Macdiarmid/Getty Images An ambulance makes its way through the crowds Photograph: Khaled Desouki/AFP/Getty Images A protester is sprayed in the eyes to help counteract the effects of teargas Photograph: Peter Macdiarmid/Getty Images Protesters suffering from the effects of teargas fired by police lie in a makeshift medical centre Photograph: Peter Macdiarmid/Getty Images A veiled protester leads chants against Field Marshal Mohamed Hussein Tantawi Photograph: Mohamed Abd El Ghany/Reuters