First they take back Manhattan. Is St Paul's protest next?

In a swoop executed with military precision in the dead of night, police moved in to demolish the two-month-old Occupy Wall Street protest camp, sparking a day of confrontations with angry demonstrators in the US financial capital.

Officers arrived without warning at 1am and demanded protesters leave Zuccotti Park with the tents, tarpaulins and other belongings that threatened to become a permanent fixture.

While some residents of the camp left of their own accord, several dozen chained themselves together and to trees and were forcibly removed. Several hundred more people, summoned by social networks, joined them in the streets throughout the night, but the New York Police Department blocked off access to the area. In less than three hours, the police had cleared the park completely and steam-cleaned the area.

Over 200 people were arrested during the operation and in the subsequent hours, as displaced protesters assembled, marched or ran through the nearby streets. Mid-morning, scores of people attempted to set up an alternative camp on a disused lot 10 minutes north of Zuccotti Park, but more than 100 police officers moved in to arrest them. Shortly before 6pm, the park was reopened and jubilant protesters flooded back in, but police searched bags and insisted that anyone trying to set up a tent or lay down a sleeping bag would be removed. For most of the day, a ring of officers in riot gear had stood guard around the perimeter of the empty park while hundreds of people gathered outside chanting slogans. The park was reopened after a judge ruled New York Mayor Michael Bloomberg was not breaching protesters' rights to free speech by preventing camping there.

Occupy Wall Street is one day shy of its two-month anniversary and organisers had been planning to step up the protests with an early-morning carnival outside the New York Stock Exchange, an occupation of the subway and a march across Brooklyn Bridge. Following the lead from New York, the City of London Corporation yesterday relaunched legal action against protesters camped outside St Paul's.

The Corporation previously offered to give the protesters until the new year to leave the site.

Stuart Fraser, policy chairman at the Corporation, said: "We paused legal action for two weeks for talks with those in the camp on how to shrink the extent of the tents and to set a departure date – but got nowhere. So, sadly, now they have rejected a reasonable offer to let them stay until the new year, it's got to be the courts. We'd still like to sort this without court action but from now on we will have to have any talks in parallel with court action – not instead."

Several US cities had managed to dismantle Occupy Wall Street camps in recent days and Toronto officials also told protesters to leave yesterday. Mr Bloomberg said the New York camp had become too unsanitary and dangerous for people to keep living there.

"From the beginning, I have said that the city has two principal goals: guaranteeing public health and safety, and guaranteeing the protesters' First Amendment rights," the mayor said.

"But when those two goals clash, the health and safety of the public and our first responders must be the priority."

People will be welcome to demonstrate at the reopened park, he said, but would have to "occupy the space with the power of argument".