Police arrested 70 protesters at New York's Zuccotti Park early Tuesday, including some who chained themselves together, while clearing the park so that sanitation crews could clean it.
The officers arrived just after midnight and handed out letters to protesters ordering them to temporarily evacuate the park. Campers were told to remove their tents and all their belongings, the New York Post reported.
The eviction letters declared, "The city has determined that the continued occupation of Zuccotti Park poses an increasing health and fire safety hazard.
"We also require that you immediately leave the park on a temporary basis so it can be cleared and restored for its intended use.
"You will be allowed to return to the park in several hours, when this work is complete. If you decide to return, you will not be permitted to bring tents, sleeping bags, tarps and similar materials with you."
A man who identified himself as a New York Police Department captain used a bullhorn to order people out of the park, saying repeatedly that a temporary evacuation was necessary to dismantle illegal structures that presented a fire hazard, The Wall Street Journal reported.
At least 400 police officers stood around all sides of the park, where dozens of people remained in place. Public buses operated by the Metropolitan Transportation Authority were seen pulling up to the site, which has been the center of the "Occupy Wall Street" movement for nearly two months.
Protesters responded by chanting "Whose Park? Our Park" and "You don't have to do this." Some protesters positioned near the encampment's kitchen linked themselves together using padlocks.
Just before 2:00am, police began to clear the park more aggressively and knocked over the tent from which protesters had been streaming video from Zuccotti Park. One protester refused to get out of the tent, and three officers in riot gear carried him away wrapped in pieces of tent and tarp.
A video stream continued to broadcast, with nearly 20,000 viewers watching the footage online.
"EVERYONE should get to the park immediately for eviction defense!" the group posted on their website.
Hours before the operation commenced, New York City Mayor Michael Bloomberg, NYPD Commissioner Ray Kelly, New York City Fire Commissioner Sal Cassano and other officials convened in secret at City Hall to greenlight the campaign to clear the park, sources told the Post.
"They're going to go in and do this because of health violations and the rising crime," said a source.
The NYPD issued a statement to FOX News Channel saying they were not making any arrests and "police are stationed at the park every night."
The raid comes just hours after "Occupy Wall Street" leaders announced their plans to wreak havoc on Thursday by shutting down Wall Street and the subways to mark the renegade group's two-month takeover of Zuccotti Park.
According to their website, the day will include "Mass, Non-violent Direct Action" to "Shut Down Wall Street" at 7:00am, "Occupy the Subways" in all five boroughs at 3:00pm and "Take the Square," referring to Foley Square, at 5:00pm.
The crackdown follows similar eviction notices being issued at protest camps in Oakland, Calif., and Portland, Ore., in the past few days amid health and safety fears.
Three sets of eviction notices have been issued to campers at "Occupy Oakland" since Friday, with 33 demonstrators arrested after failing to disperse early Monday morning, the Oakland Tribune reported.
Police have maintained a presence at the camp in Frank H. Ogawa Plaza, saying people can continue to rally but cannot camp or sleep there.
On Sunday, "Occupy Portland" protesters were evicted from their headquarters and about 50 were arrested as authorities cleaned up the parks the group had been residing in since the beginning of the demonstration in early October, the Portland Tribune reported.