Hundreds of people staged a protest on Brooklyn Bridge on Saturday as the "Occupy Wall Street" protest spread to another area of New York.
The New York Times reported that that demonstration left its main area in Zuccotti Park in Manhattan en route to the bridge shortly after 3pm local time (8pm Irish).
On what was the second week of protests by the Occupy Wall Street movement, a large group of marchers broke off from others on the bridge's pedestrian walkway and headed across the Brooklyn-bound lanes.
Both the walkway and Brooklyn-bound car lanes were shut to traffic, snarling traffic near City Hall at the Manhattan side of the bridge.
Up to 400 protesters were later arrested by police after all traffic seeking to cross the bridge was blocked for a time.
"Multiple warnings had been given to the protesters that if they took to the roadway they would be arrested," a New York police spokesperson said.
"Some complied and took the walkway without being arrested. Other locked arms and proceeded on the Brooklyn-bound vehicular roadway. The latter were arrested."
Witnesses described a chaotic scene on the famous suspension bridge as a sea of police officers surrounded the protesters using orange mesh netting.
Some protesters tried to get away as officers started handcuffing members of the group. Dozens of protesters were seen handcuffed and sitting on the span as NYPD buses were called in to take them away, witnesses and organisers said.
In addition to what they view as excessive force and unfair treatment of minorities, including Muslims, the movement is also protesting against home foreclosures, high unemployment and the 2008 bailouts.
The group has gained support among some union members. The United Federation of Teachers and the Transport Workers Union Local 100, which has 38,000 members, are among those pledging solidarity.
NYPD headquarters demonstration
As many as 2,000 people gathered in Lower Manhattan last night as part of the ongoing demonstration. They marched on New York's police headquarters to protest against arrests and police behaviour.
The New York Police Department has come in for criticism by the movement since video emerged of pepper spray being used against demonstrators last weekend.
"We got sold out!" the crowd chanted last night as it snaked through rush hour traffic, closely shadowed by columns of police.
Hand drawn placards included: "Nazi bankers" and "people before dollars."
It was the first time the protesters tried marching on New York's police headquarters at One Police Plaza.
Numbers were swelled on Friday by youths responding to false rumours on the internet that British band Radiohead was going to play a free concert at the protest camp.
Protesters added police brutality to their lengthy list of grievances after an incident a week ago when a senior officer used pepper spray against four demonstrators who had already been shut inside a police pen.
"NYPD protects billionaires and Wall Street," one placard said.