PORTLAND, Ore (Reuters) - Portland Police arrested more than 50 people on Sunday as the authorities cleared out and blocked off encampments of the Occupy movement that has been protesting nationwide over economic issues. 
 
 The Portland actions were among several by authorities around the country over the weekend to try to close down encampments occupied by demonstrators for weeks. 
 
 Encampments sprang up in several cities in recent weeks in solidarity with the Occupy Wall Street movement that began in New York in September to protest what demonstrators see as economic inequality and undue political influence by corporate interests. 
 
 In Portland the authorities had issued an eviction notice, and then moved to empty the camps and fence them off. Many protesters left on their own after the notice, but others chose to stay. 
 
 A police statement said: "the Portland Police Bureau has cleared both Chapman and Lownsdale Square parks. During today's operation, more than 50 arrests were made of people who either wanted to be arrested or refused to leave Chapman Square." 
 
 There were no injuries during the park clearance, police said. 
 
 But demonstrators regrouped in the streets, blocking traffic for hours in a standoff with ranks of Portland Police officers in riot gear. 
 
 The confrontation continued into late afternoon, but as darkness fell protesters left the streets. 
 
 A core group moved to a downtown square for speeches and to discuss their next moves and where they would spend the night, as a light rain hit the city. 
 
 More than 300 officers, including those from 10 other law enforcement agencies, had participated in the authorities' actions during the day, Portland Police said. 
 
 On the protester side, an estimated thousand people joined in demonstrating in the streets. 
 
 FACE-TO-FACE 
 
 During the afternoon confrontation police, face-to-face with the protesters, repeatedly told them that if they didn't move out of the road, or appeared to resist arrest, chemical agents and impact weapons -- apparently beanbag guns -- might be used. 
 
 On their side the protesters chanted: "I don't see no riot here, take off your riot gear," "The whole world is watching," and "We are peaceful people." 
 
 Officials also moved over the weekend to dismantle a protest camp in Salt Lake City, Utah, while in Denver, police on Saturday removed mattresses, cooking grills and tents illegally placed on a public sidewalk. 
 
 Seventeen people were arrested, Denver police said on Sunday. 
 
 This weekend's actions were the latest as officials in a number of cities have cited health and safety issues in urging Occupy demonstrators to take down their camps, or as the basis for police actions to shut them down. 
 
 Portland Mayor Sam Adams in comments to CNN on Sunday linked that city's camps to increases in crime and drug overdoses, and said an arsonist had used a camp as camouflage for his efforts. 
 
 While Adams expressed sympathy for protester goals, he said the Occupy movement needed to evolve beyond encampments "in order to get the kind of reforms we need." 
 
 In Philadelphia, Mayor Michael Nutter on Sunday ordered beefed-up police patrols at the city's protest site, saying conditions were "dramatically deteriorating." 
 
 "This movement has changed and the people have changed," he said. "We are now at a critical point where we must reevaluate our entire relationship with this very changed group." 
 
 In Salt Lake City authorities moved to dismantle a camp at a downtown park and arrested 15 people on Saturday. 
 
 In Oakland, California, the scene of previous clashes between police and demonstrators, city hall issued a third eviction notice on Sunday. It warned protesters they faced "immediate arrest" if they continued to camp out in the city's plaza and parks. 
 
 The city offered alternative emergency accommodation at two local area homeless shelters, and laid on a shuttle service to one that was not within walking distance of the encampments. 
 
 In St. Louis, Mayor Francis Slay has warned protesters they have to decamp but has offered to continue talks to find a permanent place for the protest. 
 
 (Additional reporting by Keith Coffman in Denver, Alex Dobuzinskis in Los Angeles, Tim Gaynor in Phoenix, Dave Warner in Philadelphia, and Bruce Olson in St. Louis; Writing by Ellen Wulfhorst; Editing by Jerry Norton) ||||| Several hundred protesters, some wearing goggles and gas masks, marched past authorities in a downtown street Sunday, hours after riot police forced Occupy Portland demonstrators out of a pair of weeks-old encampments in nearby parks. 
 
 A police officer drags a protester in the Portland encampment Sunday, Nov. 13, 2011, in, Portland, Ore. In a tense escalation of the Occupy Portland protest, police in riot gear Sunday surrounded demonstrators... (Associated Press) 
 
 Police officers arrest a protester in the Portland encampment Sunday, Nov. 13, 2011, in, Portland, Ore. In a tense escalation of the Occupy Portland protest, police in riot gear Sunday surrounded demonstrators... (Associated Press) 
 
 Protesters pack up and leave hours before a mandate from the city to vacate the Occupy Portland Camp in Portland, Ore., Saturday, Nov. 12, 2011.(AP Photo/Don Ryan) (Associated Press) 
 
 Hundreds of protesters and supporters gather hours before a mandate from the city to vacate the Occupy Portland Camp in Portland, Ore., Saturday, Nov. 12, 2011.(AP Photo/Don Ryan) (Associated Press) 
 
 Police officers arrests a protester in the Portland encampment Sunday, Nov. 13, 2011, in, Portland, Ore. In a tense escalation of the Occupy Portland protest, police in riot gear Sunday surrounded demonstrators... (Associated Press) 
 
 Police officers arrests protesters in the Portland encampment Sunday, Nov. 13, 2011, in, Portland, Ore. In a tense escalation of the Occupy Portland protest, police in riot gear Sunday surrounded demonstrators... (Associated Press) 
 
 An American flag and sign are visible as hundreds gather hours before a mandate from the city to vacate the Occupy Portland Camp in Portland, Ore., Saturday, Nov. 12, 2011.(AP Photo/Don Ryan) (Associated Press) 
 
 A protesters packs up hours before a mandate from the city to vacate the Occupy Portland Camp in Portland, Ore., Saturday, Nov. 12, 2011.(AP Photo/Don Ryan) (Associated Press) 
 
 A protester shouts as police officers using nightsticks push people away from the Occupy Portland encampment Sunday, Nov. 13, 2011, in, Portland, Ore. In a tense escalation of the Occupy Portland protest,... (Associated Press) 
 
 A body is removed from a tent in the Occupy Salt Lake camp in Pioneer Park, Friday Nov. 11, 2011 in Salt Lake City. The Occupy Salt Lake group has been in Pioneer Park for weeks, protesting what they... (Associated Press) 
 
 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. 
 
 More than 50 protesters were arrested in the police action, but officers did not use tear gas, rubber bullets or other so-called non-lethal weapons, police said. 
 
 After the police raid, the number of demonstrators swelled throughout the afternoon. By early evening, dozens of officers brandishing nightsticks stood shoulder-to-shoulder to hold the protesters back. Authorities retreated and protesters broke the standoff by marching through the streets. 
 
 Demonstrators regrouped several blocks away, where they broke into small groups to discuss their future. Some advocated occupying foreclosed homes, others wanted to move onto the Portland State University campus or to the shores of the Willamette River. 
 
 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. 
 
 It didn't last. 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." 
 
 "We were talking about what we were going to do and then they just started hitting people. Seems like a waste of resources to me," protester Mike Swain, 27, told the AP. 
 
 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. 
 
 Choya Adkison, 30, said police moved in after giving demonstrators a false sense of calm. They thought they had time to rest, relax and regroup, she said 
 
 "Camp was completely vulnerable, completely defenseless" when police moved in, she said. "I'm disappointed that they created a sense of trust by walking away and then completely trampled it." 
 
 City officials erected temporary chain-link fences with barbed wire at the top around three adjacent downtown parks, choking off access for demonstrators as parks officials cleaned up. 
 
 Police Chief Mike Reese told KGW-TV it was his plan to take the parks in a peaceful manner and that's what happened. 
 
 "Our officers have performed exceptionally well," he said. 
 
 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. Protesters facing them appeared to be in festive spirits with some banging on drums and plastic pails, another clanging a cowbell while others danced in the streets as a man juggled nearby. 
 
 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. Police had prepared for a possible clash, warning that dozens of anarchists may be planning a confrontation with authorities. Officers seized pieces of cement blocks Friday, saying they were told some demonstrators had plans to use them as weapons against police. They said they believe some demonstrators were building shields and trying to collect gas masks. 
 
 And police seized incendiary devices, gas masks and marijuana on Sunday after stopping three men for speeding on Interstate 5 south of Portland. The men told police they had left Occupy Portland an hour earlier and were carrying the equipment in anticipation of a confrontation with authorities, the Marion County Sheriff's Office said. 
 
 Meanwhile in Oakland, Calif., friends confirmed Sunday that Scott Olsen, the Iraq War veteran who suffered a serious head injury during a police raid on the Occupy Oakland encampment, has been released from the hospital. Olsen suffered a skull fracture during tear-gas filled clashes between police and demonstrators on Oct. 25. 
 
 Dottie Guy of Iraq Veterans Against the War said Sunday Olsen was released last week. He can now read and write, but still has trouble talking, she added. 
 
 "Considering what happened to him he's doing well," Guy said. "He does have a brain injury so there will be some kind of rehab and physical therapy needed." 
 
 Occupy Wall Street supporters nationwide have rallied around Olsen's plight. 
 
 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 did not respond to requests for comment on whether officers were preparing to forcibly clear the camp. 
 
 The eviction notices come as officials across the country urged an end to similar gatherings in the wake of three deaths in different cities, including two by gunfire. Demands for Oakland protesters to pack up increased after a man was shot and killed Thursday near the encampment site. 
 
 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. 
 
 The shooting occurred the same day a 35-year-old military veteran apparently committed suicide in a tent at a Burlington, Vt., Occupy encampment. Police said a preliminary investigation showed the veteran fatally shot himself in the head. They said the death raised questions about whether the protest would be allowed to continue. 
 
 In other cities over the weekend: 
 
 _ In Salt Lake City, police arrested 19 people Saturday when protesters refused to leave a park a day after a man as found dead inside his tent at the encampment. The arrests came after police moved into the park early in the evening where protesters had been ordered to leave by the end of the day. About 150 people had been living in the camp there for weeks. 
 
 _ In Albany, N.Y., police arrested 24 Occupy Albany protesters after they defied an 11 p.m. curfew in a state-owned park. State police officials hauled away the protesters after warning them with megaphones that they were breaking the law in Lafayette Park. They were charged with trespassing. 
 
 _ In Denver, authorities forced protesters to leave a downtown encampment and arrested four people for interfering with officers who removed illegally pitched tents, said police spokesman Sonny Jackson. 
 
 _ In San Francisco, violence marked the protest Saturday where police said two demonstrators attacked two police officers in separate incidents during a march. Police spokesman Carlos Manfredi said a protester slashed an officer's hand with a pen knife while another protester shoved an officer, causing facial cuts. He said neither officer was seriously hurt, and the assailants couldn't be located. 
 
 ___ 
 
 Associated Press writers Terry Collins in Oakland, Josh Loftin in Salt Lake City, Jim Anderson in Denver and Andrew Dalton in Los Angeles contributed to this report.
– Hundreds of defiant protesters took to the streets yesterday after cops stormed Occupy Portland encampments and busted 50 people. Mayor Sam Adams ordered the camps shut because of what he called unhealthy conditions and increased crime triggered by drug users and thieves drawn to the sites, reports AP. Authorities erected chain-link fences with barbed wire around adjacent downtown parks to block demonstrators from moving back in. "This is not a game," said Adams. Protesters are considering what action to take next. Some have proposed occupying foreclosed homes, others to move onto the state university campus or to the shores of the Willamette River. The Portland police action was the largest weekend crackdown on protests across the nation. Authorities also dismantled a camp in Salt Lake City, and Denver police removed mattresses, cooking grills and tents on a sidewalk, busting 17 protesters. Philadelphia Mayor Michael Nutter yesterday boosted police patrols at his city's protest site, saying conditions were "dramatically deteriorating," Reuters reports. The movement "has changed and the people have changed," he said. "We are now at a critical point where we must reevaluate our entire relationship with this very changed group."