Hoisting photographs of aborted fetuses, militant anti-abortionists staged a boisterous sit-in Saturday in a finale to a three-day campaign that led to more than 900 arrests.

Police said between 500 and 550 arrests were made Saturday as some 1,500 anti-abortion demonstrators and their opponents surrounded the Family Planning Associates building in the largest of the demonstrations that began Thursday.The protest began shortly after daybreak under leaden skies and a light drizzle. The weather worsened as the clinic was besieged and arrests began shortly after 10 a.m. in a downpour.

No one was hurt, but an ambulance was called for one protester who passed out.

Pro-abortion forces called it "pure pandemonium."