A protester holds an Egyptian flag as he stands in front of water canons during clashes in Cairo January 28, 2011. Police and demonstrators fought running battles on the streets of Cairo on Friday in a fourth day of unprecedented protests by tens of thousands of Egyptians demanding an end to President Hosni Mubarak’s three-decade rule. REUTERS/Yannis Behrakis (EGYPT – Tags: CIVIL UNREST POLITICS IMAGES OF THE DAY) FOR BEST QUALITY IMAGE SEE: GM1E7AO1KUV01 – RTXX7EN