NEW YORK - Police wearing helmets and carrying shields evicted protesters with the Occupy Wall Street movement early on Tuesday from the park in New York City's financial district where they have camped since September, dismantling their tent city and arresting about 70 people.

Authorities declared that the continued occupation of Zuccotti Park - which had become a sea of tents, tarps and protest signs with hundreds of demonstrators sleeping there - posed a health and safety threat.

Police spokesman Paul Browne said that about 70 protesters were arrested in the park during the nighttime operation for defying orders to leave and several more were arrested nearby, although most left voluntarily.

About a dozen protesters had chained themselves together and another two had chained themselves to trees before being cut loose and removed, Browne added.

New York City Mayor Michael Bloomberg defended the move to evict the protesters and tear down their tent city.

"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. There have been reports of businesses being threatened and complaints about noise and unsanitary conditions that have seriously impacted the quality of life for residents and businesses in this now-thriving neighborhood," Bloomberg said in a statement.

The protesters had set up camp in Zuccotti Park on Sept 17 to protest a financial system they say mostly benefits corporations and the wealthy. Their movement has inspired similar protests against economic inequality in other cities, and in some cases have led to violent clashes with police.

The mayor said protesters and the general public can return once the park is cleaned, but would have to abide by rules banning items like tents, tarps and sleeping bags.

"Protesters have had two months to occupy the park with tents and sleeping bags. Now they will have to occupy the space with the power of their arguments," Bloomberg said.

Protesters vowed that the eviction from the park that had become the epicenter of their movement would not deter them and several hundred congregated at another lower Manhattan square.

Police barricaded streets around the park, which had been lit up with spotlights. Authorities swept up and removed mounds of debris.

Reuters