PORTLAND, Ore. — Police say they believe some people inside the Occupy Portland encampments are preparing for a confrontation when officers attempt to clear the parks.

Occupy Portland organizers say the movement is nonviolent and have appealed to people in the camp to resist peacefully when the midnight Saturday deadline arrives.

But authorities said Friday that a call for reinforcements has gone out to other cities, and as many as 150 anarchists may come to Portland. Police also say some elements may be building shields and looking for gas masks.

Mayor Sam Adams has ordered the camp shut down, citing unhealthy conditions and the encampment's attraction of drug users and thieves

On Friday, demonstrators began dismantling a kitchen tent, and some people left. Others vowed to stay unless taken away in handcuffs.