Roy Bourgeois and about a dozen supporters had marched down the main boulevard leading to the Vatican holding a banner "Ordain Catholic Women" and chanting outside St. Peter's Square "What do we want? Women priests! When do we want them? Now!"

Police prevented the group from entering the piazza and told them to take down their banners since they didn't have a protest permit. When police tried to confiscate the banners, members of the group resisted, resulting in Bourgeois and two supporters being taken away in police cars, witnesses said.

The three were detained for about two hours at a Rome police station and released without being arrested or charged, though prosecutors were still investigating, said Bourgeois' attorney, Bill Quigley.