Chanting and waving flags, thousands of Muqtada al-Sadr's followers filled Firdous Square to protest a proposed U.S.-Iraqi security pact that would allow American troops to stay for three more years. The Bush effigy was placed on the same pedestal where U.S. Marines toppled the ousted dictator's statue in one of the iconic images of the 2003 U.S.-led invasion.

After a mass prayer, demonstrators pelted the effigy with plastic water bottles and sandals. One man hit it in the face with his sandal. The effigy fell head first into the crowd and protesters jumped on it before setting it ablaze.

Before it fell, the effigy held a sign that said: "The security agreement ... shame and humiliation."

Iraq's parliament is expected to vote next week on the plan to keep U.S. forces in Iraq for another three years. But the noisy opposition by the Sadrists indicates that even if it is approved, the deal could remain divisive in a country struggling for reconciliation.