Police in riot gear and biohazard suits have removed anti-Wall Street activists from a camp outside Los Angeles City Hall, arresting about 200 people.
More than 1000 police arrived after midnight local time to enforce a mayoral eviction order, arresting those who would not leave voluntarily.
Officials say the eviction took four hours and was mostly peaceful, although several people had to be removed from trees.
The Los Angeles activists had been camped out for eight weeks as part of the two month old Occupy movement that began in New York.
The demonstrators are protesting against economic inequality and alleged excesses of the United States financial system.
City officials had complained of crime, sanitation problems and property damage.
In Philadelphia, about 100 protesters left their Occupy camp peacefully but 52 were arrested some time later on mostly minor disorder charges.