Police in Oakland, California have cleared out anti-Wall Street demonstrators who had set up camp at the City Hall plaza, and arrested more than 30 people.

The police, dressed in riot gear, took action Monday. The office of Mayor Jean Quan issued a statement saying the effort took place “smoothly and peacefully.” The statement also said that there was repeated violence, as well as a murder, at the encampment. Quan said the encampment has been a tremendous drain on the city.

Earlier in the month, police used tear gas when a number of protesters temporarily shut down the Port of Oakland, one of the busiest seaports in the United States. Marchers blocked gates and tried to take over an empty building. Oakland city officials say marchers also broke windows, splashed paint on storefronts, and set fires in the downtown business district. Supporters of the Occupy movement condemned the violence and vandalism that broke out during that particular protest. Police arrested dozens of people and several protesters were hurt.

Monday’s police operation in Oakland occurred one day after authorities in Portland, Oregon arrested more than 50 people while evicting protesters from a site there.

The protests are part of a loosely tied nationwide movement against corporate greed and economic inequality that began in New York in September.