The National Lawyers Guild said it has obtained a court order that allows Occupy Wall Street protesters to return with tents to a New York City park.
The injunction prevents the city from enforcing park rules, which were published after the Occupy Wall Street protest began.
Those rules would bar protestors from bringing tents, tarps and sleeping bags into the park.
At a morning news conference at City Hall, Mayor Michael Bloomberg said the city knew about the court order but had not seen it and would go to court to fight it. He said the city wants to protect people's rights, but if a choice must be made, it will protect public safety.
A hearing is scheduled for 11 am.
Zuccotti Park was cleared overnight so that crews could clean it. Bloomberg said that was done "to reduce the risk of confrontation."
He said the city had planned to allow the protesters back in the park after it was cleaned. Under the city's plans, protesters would not be allowed to use tents, sleeping bags, or tarps and would have to follow all park rules.
Protestors had been heading back to Zuccotti Park, but after the court order was issued, the city closed it again while it assesses the court order.
Hundreds of police officers in riot gear raided Zuccotti Park early Tuesday, evicting dozens of Occupy Wall Street protesters from what has become the epicenter of the worldwide movement protesting corporate greed and economic inequality.
Hours later, the National Lawyers Guild obtained a court order allowing Occupy Wall Street protesters to return with tents to the park. The guild said the injunction prevents the city from enforcing park rules on Occupy Wall Street protesters.
About 70 people were arrested overnight, including some who chained themselves together, while officers cleared the park so that sanitation crews could clean it.
By 9 a.m., the park was power-washed clean. Police in riot gear still ringed the public space, waiting for orders to reopen it.
The city told protesters at the two-month-old encampment they could come back after the cleaning, but under new tougher rules, including no tents, sleeping bags or tarps, which would effectively put an end to the encampment if enforced.
Bloomberg said the evacuation was conducted in the middle of the night "to reduce the risk of confrontation in the park, and to minimize disruption to the surrounding neighborhood."
"The law that created Zuccotti Park required that it be open for the public to enjoy for passive recreation 24 hours a day," Bloomberg said. "Ever since the occupation began, that law has not been complied with, as the park has been taken over by protesters, making it unavailable to anyone else."
Concerns about health and safety issues at Occupy Wall Street camps around the country have intensified, and protesters have been ordered to take down their shelters, adhere to curfews and relocate so that parks can be cleaned.
Hundreds of former Zuccotti Park residents and their supporters marched along Lower Manhattan before dawn Tuesday.
Some paused and locked arms outside the City Hall gates but left peacefully when police in riot gear appeared on the scene. About 300 to 400 kept moving along the sidewalks, taking care not to block them.
Some were chanting, "This is what democracy looks like."
Others chanted: "Hey, hey, ho, ho, our billionaire mayor has got to go."
At about 1 a.m. Tuesday, New York City police handed out notices from Brookfield Office Properties, owner of Zuccotti Park, and the city saying that the park had to be cleared because it had become unsanitary and hazardous.
Paul Browne, a spokesman for the New York Police Department, said the park had been cleared by 4:30 a.m. and that about 70 people who'd been inside it had been arrested, including a group who chained themselves together. One person was taken to a hospital for evaluation because of breathing problems.
Police in riot gear filled the streets, car lights flashing and sirens blaring. Protesters, some of whom shouted angrily at police, began marching to two locations in Lower Manhattan where they planned to hold rallies.
Some protesters refused to leave the park, but many left peacefully. Ben Hamilton, 29, said he was arrested "and I was just trying to get away" from the fray.
Rabbi Chaim Gruber, an Occupy Wall Street member, said police officers were clearing the streets near Zuccotti Park.
"The police are forming a human shield, and are pushing everyone away," he said.
Hundreds of police officers surrounded the park in riot gear with plastic shields across their faces, holding plastic shields and batons which were used on some cases on protesters.
Police also came armed with klieg lights, which they used to flood the park, and bull horns to announce that everyone had to clear out.
Jake Rozak, another protester, said police "had their pepper spray out and were ready to use it."
Notices given to the protesters said the park "poses an increasing health and fire safety hazard to those camped in the park, the city's first responders and the surrounding community."
It said that tents, sleeping bags and other items had to be removed because "the storage of these materials at this location is not allowed." Anything left behind would be taken away, the notices said, giving an address at a sanitation department building where items could be picked up.
Alex Hall, 21, of Brooklyn, said police walked into the park "stepping on tents and ripping them out."
Occupy encampments have come under fire around the country as local officials and residents have complained about possible health hazards and ongoing inhabitation of parks and other public spaces.
Anti-Wall Street activists intend to converge at the University of California, Berkeley on Tuesday for a day of protests and another attempt to set up an Occupy Cal camp, less than a week after police arrested dozens of protesters who tried to pitch tents on campus.
The Berkeley protesters will be joined by Occupy Oakland activists who said they would march to the UC campus in the afternoon. Police cleared the tent city in front of Oakland City Hall before dawn Monday and arrested more than 50 people amid complaints about safety, sanitation and drug use.