On Saturday, for the third consecutive night, dozens of demonstrators defied the curfew and inhabited the site, chanting and waving signs and huddling for warmth in the 40-degree weather. The police made no new arrests overnight.

In Denver, most of the arrests on Saturday were over a police rule prohibiting structures, including tents, from being erected in public parks. Some accounts said that tensions escalated when the protesters climbed the State Capitol’s steps during a march by as many as 2,000 people. No public demonstrations are allowed on the steps without a permit.

But a media liaison with Occupy Denver, Jeannie Hartley, said on Sunday that the protesters had never made it to the steps, which were blocked off.

Most of the 20 arrests, a police spokesman said, were made when officers moved to keep people from erecting tents across the street from the Capitol at Civic Center Park. Several videos showed the police using pepper spray. Two protesters were arrested and charged with felony assault on a police officer after officials said he was knocked off his motorcycle, and other officers were kicked, said the spokesman, Lt. Matt Murray.

Lieutenant Murray said that the police requested reinforcements after the officer was knocked off his motorcycle and that the enlarged force then moved into the park where most of the arrests were made.

One video posted on the Occupy Denver Facebook page also clearly showed tension and conflict within the protesters’ ranks. At one point, a man, shouting in anger, is seen being pushed from the crowd to confront the officers, who are lined up with shields and batons.