Riot policemen stand on a bridge as protesters gather at a crossroads leading to the U.S. embassy in Sanaa September 14, 2012. Security forces in Yemen fired warning shots and used water cannons against hundreds of protesters near the U.S. embassy in Sanaa on Friday, a day after demonstrators angered by a film deemed blasphemous to Islam stormed the fortified compound. REUTERS/Khaled Abdullah (YEMEN - Tags: POLITICS CIVIL UNREST RELIGION)