CHICAGO — Chicago police arrested about 175 protesters early Sunday in an operation to clear the city's Grant Park of demonstrators camping out in protest against corporate greed, police said.

A police department spokesman said the "Occupy Chicago" protesters were given several warnings to leave the park before officers moved in and began hauling them away.

"They were in park property after hours," said Officer Robert Perez. "There is a municipal ordinance that nobody is allowed in the park after 11 pm."

He said about 175 people were arrested and taken to a district police station for processing. Typically people arrested for violating city ordinances are then released under their own signature unless they are wanted for other offenses, he said.

The Chicago Tribune said protesters, who had formed a human chain and were seated on the ground when the police moved in, were cheering as they were hauled away in police paddy wagons and city buses.

About 150 other protesters continued the demonstration from across the street on Michigan Avenue, it reported.

At one point, protesters began chanting "the whole world is watching," evoking a now famous cry that went up during a violent confrontation between protesters and police at Grant Park during the 1968 Democratic Convention.

The current protests are an offshoot of the Occupy Wall Street protests which began in lower Manhattan but have since spread to other cities.