Hundreds of police officers in riot gear raided the New York City park where the Occupy Wall Street protests began, evicting and arresting dozens of protesters, before dawn, from what has become the epicentre of the worldwide movement protesting at corporate greed and economic inequality.

Hours later, the National Lawyers Guild obtained a court order allowing the protesters to return with their tents to the park, where they have camped for two months. The guild said the injunction prevents the city from enforcing park rules on the protesters.

At a morning news conference, New York mayor Michael Bloomberg said the evacuation was conducted in the middle of the night “to reduce the risk of confrontation in the park, and to minimise disruption to the surrounding neighbourhood”.

Hundreds of police officers surrounded the park overnight in riot gear, holding plastic shields and batons which were used in some cases on protesters. Police flooded the park with klieg lights and used bull horns to announce that everyone had to leave.

Police “had their pepper spray out and were ready to use it”, said protester Jake Rozak.

About 70 people were arrested during the night between Monday and Tuesday, including some who chained themselves together. Others chanted or shouted angrily at police and vowed to march in protest.

Mr 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. By 9 a.m. the park was power-washed clean by sanitation workers. Police in riot gear ringed the public space, waiting for orders to reopen it.

The city told protesters 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.

“The law that created Zuccotti Park required that it be open for the public to enjoy for passive recreation 24 hours a day,” Mr 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 US 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 yesterday.