Thousands of demonstrators have come out in Rome to protest against globalization and U.S. President George Bush, who was winding up a European tour.
The demonstrators filled Rome's streets as the President met with Pope Benedict at the Vatican.
It was President Bush's first meeting with Pope Benedict since the former Cardinal was elected to lead the world's Roman Catholics in 2005.
During their half hour meeting, they discussed many subjects including the Israeli-Palestinian conflict and the war in Iraq.
The pope told the U-S president he would like a "regional and negotiated" solution to conflicts in the Middle East.
But as the pope spoke of peace, thousands of protesters gathered in Rome to demonstrate against the U.S. president. Security in the city was extremely tight.
The Italian authorities deployed 10,000 police officers to ensure that no violence would erupt as tens of thousands of marched through the streets to also protest against wars and the deployment of troops in foreign countries.
Anti-globalization protesters and leftists carried out what was a peaceful demonstration, for the most part, as helicopters hovered overhead.
Peace activists carried rainbow-colored peace flags and banners, which read "No to Wars" and "Bush out".
She says, "There are a lot of people who are here to demonstrate their opposition to overpowering and violence personified by the man who is here, welcomed with great honor as a friend, while instead he should be treated for what he is: that is an assassin responsible of the worst crimes."
One moment of tension came when the demonstration entered the central Piazza Venezia and was greeted by police in full riot gear with helmets on and shields up.
In the end, violence erupted as a group of demonstators put on facemasks in defiance of a police order, and threw bottles and other objects at the police.
The police responded with tear gas. The U-S President will travel to Albania and Bulgaria next before returning to Washington on Monday.