NEW YORK (AFP) -- Police flooded into the New York cradle of the U.S. anti-Wall Street movement early Tuesday, driving out demonstrators and tearing down the tent camp in what officials said was a temporary eviction.

The surprise crackdown at the birthplace of the movement, launched after similar evictions in other cities, signaled a tougher line by U.S. authorities towards the two-month old protests against Wall Street and Washington elites.

New York’s Zuccotti Park has been the symbolic epicenter of a movement that has spread to several U.S. cities and inspired similar action across the world.

But by 2 a.m. most of the hundreds of protesters who had been gathering in the park had heeded the calls to leave, with around a dozen holdouts surrounded by police, according to an AFP correspondent.

Police wearing helmets but not full riot gear had shoved groups of protesters into trucks, while clean-up crews tore down tents and garbage trucks carted away piles of signs beneath a circling helicopter.

“Liberty Square (Zuccotti Park), home of Occupy Wall Street for the past two months and birthplace of the 99% movement that has spread across the country and around the world, is presently being evicted by a large police force,” the demonstrators said in a statement.

New York mayor Michael Bloomberg’s office urged the protesters to “temporarily” leave the area, saying they could return later.

“Occupants of Zuccotti should temporarily leave and remove tents and tarps. Protestors can return after the park is cleared,” the office said on the micro-blogging website Twitter.

Plans to temporarily clear the privately-owned square so that it could be cleaned had been put on hold at the last minute one month ago in what the protesters hailed as a victory.

But on Tuesday the police took the demonstrators by surprise in the early morning raid, with one protester saying they “came running up like an army.”

“The whole world is watching!” another protester shouted as he was dragged away by police.

The demonstrations against corporate greed and Washington gridlock have seen an eclectic group of mainly young people set up tents in city squares across the country in what some authorities see as a threat to public safety.

Early on Monday riot police had dismantled a similar protest camp in the Californian city of Oakland, across the bay from San Francisco, arresting more than 30 protesters in the second such action on the West Coast in two days.

Fueling the sense of turmoil, a top advisor to the mayor of Oakland, where demonstrations have repeatedly descended into clashes in recent weeks, resigned in protest at the clampdown.

Oakland Mayor Jean Quan said the early morning operations was prompted by a recent murder that happened adjacent to the camp.

“The encampment had become a place where we had repeated violence and this week a murder,” Quan told reporters. “We had to bring the camp to an end before someone else got hurt.”

But hours later a top legal advisor, civil rights attorney Dan Siegel, announced that he had resigned in protest shortly before the crackdown.

“No longer Mayor Quan’s legal advisor. Resigned at 2 am. Support Occupy Oakland, not the one percent and its government facilitators,” he wrote on Twitter. His resignation was later confirmed by Quan.

The protests, coming a year ahead of presidential and congressional elections, have brought together a loose coalition of mainly liberal Americans opposed to the “one percent” of business and political elites.

The demonstrators accuse Washington of enabling the bankers that brought down the American economy in 2008 and have said they are inspired by the Arab Spring revolts that have convulsed the Middle East.