Police have moved into the Occupy Wall Street encampment at New York City's Zuccotti Park and arrested 70 protesters as the park was cleared for a thorough cleaning.

Some of the arrests were of protesters who chained themselves together this morning.

At about 1 a.m. New York City police handed out notices from the city and the owner of the park, saying that it had to be cleared because it had become unsanitary and hazardous. Protesters were told they could return in several hours, but without sleeping bags, tarps or tents.

NYPD spokesman Paul Brown says the park was cleared by 4:30 a.m.

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.