Police cleared out the New York cradle of the anti-Wall Street protests early Tuesday in the wake of clampdowns in other US cities, and casting doubt on the future of the two-month global movement.

Hundreds of police moved into Zuccotti Park before dawn, tearing down tents in a surprise strike against the birthplace of Occupy Wall Street, protestors said.

The Manhattan park, just meters from Wall Street and the New York Stock Exchange, has been home to protesters since September 17, becoming the symbolic epicenter of a movement that has spread to several US cities and inspired similar action around the world.

Tuesday\'s raid signaled a tougher line by US authorities towards the protests, as across the Atlantic London officials also said they would resume legal action to clear a camp outside St Paul\'s Cathedral.

The rapid police operation, launched at around 1:00 am (0600 GMT), drove most of the protesters out of the square within an hour, with many heeding orders to leave while others were shoved into police vans and buses.

Police cordoned off the area, while clean-up crews tore down tents and pressure-cleaned the area as garbage trucks carted away piles of signs and belongings.

Around a dozen protesters held out for a few hours longer, but by 4:30 am (0930 GMT) the square was completely clear, according to AFP correspondents.

But as the day dawned, confusion reigned when a judge stayed the eviction order as well as the implementation of rules by the park\'s owners, Brookfield Properties, banning protestors from returning with tents and tarps.

"We are now ready to reopen the park, but understand there is a court order enjoining us from enforcing Brookfield\'s rules, so it will remain closed until we can clarify that situation," New York Mayor Michael Bloomberg told a news conference.

About 300 protestors re-grouped in a parking lot between Sixth Avenue and Grand Street, awaiting a court hearing set for 11:30 am (1630 GMT) at which lawyers for Occupy Wall Street were planning to challenge the eviction.

"Our park is in a legal battle. We have to occupy this place to show the world our commitment," said one of the participants, asking not to be named.

Police declined to say how many people had been arrested overnight, but AFP correspondents saw several dozen being hauled away.

Bloomberg defended the operation, saying the protesters had the right to make their views known and could return to the park to protest, but would not be allowed to camp out there.

"Unfortunately, the park was becoming a place where people came not to protest, but rather to break laws, and in some cases, to harm others," he said.

Small business owners in the area had complained about the noise and unsanitary conditions in the camp, accusing the demonstrators of trashing their store bathrooms and driving away customers.

Tuesday\'s raid appeared to have taken the demonstrators by surprise.

"I was dead asleep. Then I was like, oh man, there was cops kicking the tents and people yelling \'this is not a drill!\'" said Mutsukai Iroppoi, 22.

Alden Bevington, 35, another protester, said he was also caught off guard.

"I was asleep. Then the lights came on. It was designed to freak people out, an overwhelming show of force. ... There was zero violence from what I saw."

The demonstrations against corporate greed have seen an eclectic group of mainly young people set up tent cities across the country.

On Monday riot police dismantled a similar protest camp in Oakland, California arresting more than 30 protesters. Some 50 protesters were arrested in Portland, also on the West Coast, on Sunday.

Meanwhile, the City of London Corporation said in a statement it had voted to continue with litigation to clear dozens of tents at St Paul\'s Cathedral in the capital\'s financial district.

"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," said Stuart Fraser, the authority\'s policy chairman.

Activists at the St Paul\'s camp expressed anger and defiance at what happened in New York.

"It\'s disgusting (what happened in Wall Street). But this is a long-term movement. This is a movement of right now and we are not going to be stopped," said Anthony Anamasi, a bearded protester originally from New York.