ROME, Italy (CNN) -- Amid tight security measures, thousands of demonstrators marched through Rome on Friday to protest the visit of President Bush to Italy and that country's participation in the war in Iraq.
Protesters swarmed the streets of central Rome after Bush met with Pope John Paul II, one of the strongest critics of the war. Police estimated the number of demonstrators at 500,000.
Authorities deployed 10,000 police in strategic sites in anticipation of violence. The crowd was boisterous but relatively peaceful.
The protests took place at the Piazza Venezia, the site of Italy's Tomb of the Unknown Soldier. Bush had been scheduled to lay a wreath at the tomb, but those plans had to be scrapped for security reasons.
Bush instead laid a wreath at Fosse Ardeatine, the site of a World War II atrocity in which Nazis occupying Italy killed 335 men and boys, many of them Jews.