Undercover Israeli police officers detain a protester (front) during clashes in Umm el-Fahm October 27, 2010. Israeli police on Wednesday fired tear gas and stun grenades to disperse Arabs who were protesting against a rally by ultranationalist Jews in the Israeli-Arab city. Riot police charged about 200 Arabs who threw stones at them before retreating, police spokesman Micky Rosenfeld said. REUTERS/Nir Elias (ISRAEL - Tags: CIVIL UNREST POLITICS)