Police arrested many protesters in several cities Sunday as the Occupy movement spread nationwide since it started from the Wall Street in New York 30 days ago.

Protestors chant slogans during a demonstration in San Francisco, the U.S., on Oct. 12, 2011. Hundreds of protestors attended the demonstration on Wednesday to respond the Occupy Wall Street protest and to protest against the high umemployment rate and the wide gap between the rich and the poor. [Liu Yilin/Xinhua]

Nearly 175 protesters who participated in the anti-Wall Street moverment were arrested in Chicago around midnight Saturday, Xinhua reported.

Approximately 2,000 people marched in downtown Chicago on Saturday night and assembled in a plaza of Grant Park. Some of them insisted to stay by setting up tents and sleeping bags.

Police said they gave protesters repeated warnings after the park closed at 11 pm and began making arrests when they refused to leave, claiming that they were violating municipal code and would face fines.

In Washington, D.C., 19 people were arrested by Supreme Court Police,  CNN quoted a spokeswoman as saying.

According to CNN reports, New York authorities arrested 78 people on Saturday in citywide protests and 14 others for violating a midnight curfew by sitting in a fountain with no water at Washington Square Park.   

Another roughly 20 protesters were arrested late on Saturday in Raleigh, North Carolina, and about 50 were arrested in Phoenix, Reuters reported.

American protesters are angry that U.S. banks are enjoying booming profits after getting bailouts in 2008, while many ordinary Americans are struggling to make their ends meet in a difficult economy with more than 9 percent jobless. 

"Occupy Wall Street" protests, which initially targeted corporate greed, have spread to cities in more than 80 countries around the world.