PORTLAND, Ore. (AP) – Several hundred protesters, some wearing goggles and gas masks, marched past authorities in a downtown street Sunday, hours after riot police drove Occupy Portland demonstrators out of a pair of weeks-old encampments in nearby parks.

Police moved in shortly before noon and drove protesters into the street after dozens remained in the camp in defiance city officials. Mayor Sam Adams had ordered that the camp shut down Saturday at midnight, citing unhealthy conditions and the encampment’s attraction of drug users and thieves.

The number of demonstrators began to swell following the raid and increased throughout the afternoon. By early evening, hundreds of officers brandishing nightsticks stood shoulder-to-shoulder to hold the protesters back.

In the hours after the midnight eviction deadline, the anti-Wall Street protesters and their supporters had flooded the park area even as authorities in other cities across the nation stepped up pressure against demonstrators, arresting dozens of people.

At one point overnight, the Portland crowd swelled to thousands. As dawn arrived, riot police had retreated and most of the crowds had gone home, but protesters who have been at the two parks since Oct. 6 were still there, prompting one organizer to declare the night a victory for the movement.

“We stood up to state power,” Jim Oliver told The Associated Press.

Police moved in later as demonstrators held a midday “general assembly” meeting to discuss their next moves. An officer on a loudspeaker warned that anyone who resisted risked arrest and “may also be subject to chemical agents and impact weapons.” Demonstrators chanted “we are a peaceful protest.”

One man was taken away on a stretcher; he was alert and talking to paramedics, and raised a peace sign to fellow protesters, who responded with cheers.

City officials erected temporary barbed-wire fences around three adjacent downtown parks, choking off access for demonstrators as parks officials cleaned up.

Even ahead of the police raid, the camp was a shadow of what it had been before Saturday. A large segment of campers were homeless people drawn to the free food and shelter offered by Occupy Portland. They are gone, after outreach workers went through the camp to help them find shelter elsewhere.

And as the Saturday midnight eviction deadline neared, protesters themselves began dismantling tents.

Around 4 a.m., dozens of police formed a line across from demonstrators who had poured into the street.

On Sunday at an impromptu news conference, the mayor defended his order to clear the park, saying it is his job to enforce the law and keep the peace. “This is not a game,” Adams said.

Officials said that one officer suffered minor injuries when he was hit by some kind of projectile in the leg.

Also Sunday, for the third time in three days, Oakland city officials warned protesters that they do not have the right to camp in the plaza in front of City Hall and face immediate arrest.

Police officials have said a preliminary investigation suggested the shooting resulted from a fight between two groups of men at or near the encampment. Investigators do not know if the men in the fight were associated with Occupy Oakland, but protesters said there was no connection between the shooting and the camp.