Police in Boston arrested 129 protesters Tuesday, a police spokesman said, in one of the biggest crackdowns so far on the Occupy Wall Street movement sweeping the United States.

Boston Police Department spokesman Eddy Chrispin said "a majority" had been arrested for unlawful assembly when police converged on the crowd in the early hours of the morning.

"Everyone who was arrested opted to be arrested," Chrispin told AFP by telephone, after the protesters refused to obey a police request to disperse peacefully.

On its website, Occupy Boston said "hundreds of police officers in full riot gear" had "brutally attacked" its protesters along the Rose Kennedy Greenway, a string of parks named after the mother of late president John F. Kennedy.

Tents were destroyed and personal belongings thrown into the trash during the crackdown that began around 1:30 a.m. (0530 GMT).

"It's unacceptable," said one protester, Anasstassia Baichorova, from neighboring Cambridge where Harvard University is located. "We have the freedom of assembly."

Photographs on the Occupy Boston website showed police in regular uniforms, without helmets or heavy protective clothing, rounding up protesters and binding their hands with plastic handcuffs.

Some 700 police officers descended on the protesters, who numbered in the thousands, said Jake Wark, spokesman for Suffolk County district attorney (prosecutor) Daniel Conley.

"Because so many people were involved, they were brought to police stations across the city," Wark said.

"We have 18 that will be arraigned today at Boston municipal court," he added. "Another 35 or so will be split up as we review the charges. Many were bailed out last night from the police stations."

The Boston Globe newspaper quoted protesters as chanting: "The people united will never be defeated," "This is a peaceful protest" and "The whole world is watching."

One officer was punched in the face, but no protesters or police were injured, it quoted police as saying.

Chrispin said protesters were initially allowed by the city to settle into Dewey Square, an open downtown plaza, but then "they grew substantially in number and took over" adjoining green spaces and city streets.

Boston Mayor Thomas Menino defended the crackdown, telling the Globe: "I understand they have freedom of speech and freedom of expression, but we have a city to manage... Civil disobedience will not be tolerated."

"I agree with them on the issues," Menino added. "Foreclosure. Corporate greed. These are issues I've been working on my entire career. But you can't tie up a city."

Most of those arrested were freed on bail pending a court appearance later Tuesday, Chrispin said.

On its website, Occupy Boston appealed to the public for at least $4,000 to cover legal defense costs. By 2:30 pm (1830 GMT), nearly $10,000 had been collected on the wepay.com website.

Since the first group of activists started camping out in New York, demonstrations have spread to many American cities to condemn corporate greed and Wall Street's perceived stranglehold on US politics.

Photo: Flickr user qwrrty.