Occupy Oakland protester Mike Clift runs from teargas early Thursday morning, Nov. 3, 2011, in Oakland, Calif. Following a mainly peaceful day-long protest by thousands of anti-Wall Street demonstrators,... (Associated Press) 
 
 A protest that shut down the Port of Oakland to show the broadening reach of the Occupy Wall Street movement ended in violence when police in riot gear arrested dozens of protesters who broke into a vacant building, shattered downtown windows and set blazes along the way. 
 
 At least four protesters were hospitalized Thursday with various injuries, including one needing stitches after fighting with an officer, police said. Several officers were also injured but didn't need hospitalization. 
 
 "We go from having a peaceful movement to now just chaos," protester Monique Agnew, 40, said early Thursday. 
 
 Protesters also threw concrete chunks, metal pipes, lit roman candles and molotov cocktails, police said. 
 
 The far-flung movement of protesters challenging the world's economic systems and distribution of wealth has gained momentum in recent weeks, capturing the world's attention by shutting down one of the nation's busiest shipping ports toward the end of a daylong "general strike" that prompted solidarity rallies across the U.S. 
 
 Several thousand people converged on the Port of Oakland, the nation's fifth-busiest harbor, in a nearly five-hour protest Wednesday, swarming the area and blocking exits and streets with illegally parked vehicles and hastily erected, chain-link fences afterward. 
 
 Port spokesman Isaac Kos-Read said evening operations had been "effectively shut down." 
 
 Port officials hoped to resume maritime operations Thursday "and that Port workers will be allowed to get to their jobs without incident. Continued missed shifts represent economic hardship for maritime workers, truckers, and their families, as well as lost jobs and lost tax revenue for our region." 
 
 Supporters in New York, Philadelphia, Los Angeles and elsewhere staged smaller-scale demonstrations. Each group said its protest was a show of support for the Oakland movement, which became a rallying point when an Iraq War veteran was seriously injured in a clash with police last week. 
 
 The larger Occupy movement has yet to coalesce into an organized association and until the port shut down had largely been limited scattershot marches, rallies and tent encampments since it began in September. 
 
 Organizers in Oakland viewed the strike and port shutdown as a significant victory. Police said that about 7,000 people participated in demonstrations throughout the day that were peaceful except for a few incidents of vandalism at local banks and businesses. 
 
 In Philadelphia, protesters were arrested earlier Wednesday as they held a sit-in at the headquarters of cable giant Comcast. 
 
 In New York, about 100 military veterans marched in uniform and stopped in front of the New York Stock Exchange, standing in loose formation as police officers on scooters separated them from the entrance. On the other side was a lineup of NYPD horses carrying officers with nightsticks. 
 
 "We are marching to express support for our brother, (Iraq war veteran) Scott Olsen, who was injured in Oakland," said Jerry Bordeleau, a former Army specialist who served in Iraq through 2009. 
 
 The veterans were also angry that returned from war to find few job prospects. 
 
 "Wall Street corporations have played a big role in the wars in Iraq and Afghanistan," said Bordeleau, now a college student. He said private contractors have reaped big profits in those countries. 
 
 A New York Post editorial on Thursday called on protesters camped out in Manhattan to leave or have police evict them. 
 
 "What began as a credible protest against bank bailouts, crony capitalism and the like has, in large measure, been hijacked by crazies and criminals," it said. 
 
 In Boston, college students and union workers marched on Bank of America offices, the Harvard Club and the Statehouse to protest the nation's burgeoning student debt crisis. They said total outstanding student loans exceed credit card debt, increase by $1 million every six minutes and will reach $1 trillion this year, potentially undermining the economy. 
 
 "There are so many students that are trying to get jobs and go on with their lives," said Sarvenaz Asasy, of Boston, who joined the march after recently graduating with a master's degree and $60,000 in loan debt. "They've educated themselves and there are no jobs and we're paying tons of student loans. For what?" 
 
 ___ 
 
 Associated Press writers Garance Burke and Marcus Wohlsen and Beth Duff-Brown in San Francisco, Mark Pratt in Boston, JoAnn Loviglio in Philadelphia, Jon Fahey and Verena Dobnik in New York and Christina Hoag in Los Angeles contributed to this report. ||||| OAKLAND -- A long day of mostly peaceful protest in Oakland descended into chaos after midnight. Masked vandals shattered windows, set fires and plastered downtown businesses with graffiti before police moved in, dispersing crowds with tear gas and flash-bang grenades and making dozens of arrests. 
 
 Buildings that had windows smashed early today around City Hall included a Men's Wearhouse store, a dental office and the headquarters of the police internal affairs division. 
 
 Graffiti was everywhere - from anarchist symbols to threatening gang tags. Messages included "Oakland commune" and "kill cops." 
 
 The street clashes - which hospitalized three protesters and left several officers with minor injuries - happened near Occupy Oakland's tent city in Frank Ogawa Plaza at 14th Street and Broadway, which had been the center of Wednesday's general strike. That event peaked when thousands of people angry at economic inequality marched to the Port of Oakland, shutting it down. 
 
 Most of those people had gone home by 11 p.m. Wednesday, when dozens of protesters took over a vacant two-story building at 16th Street and Broadway - two blocks from the encampment - that once housed the nonprofit Travelers Aid Society. 
 
 Hundreds of others looked on as protesters barricaded the block at both ends with wooden pallets, trash cans, tables and tires. They hung banners from the building's roof, spray-painted its exterior and chanted, "Whose street, our street!" One group of protesters broke cement blocks into baseball-size rocks. 
 
 Police had kept their distance from Occupy Oakland protesters since coming under scrutiny for deploying tear gas and flash-bang grenades and firing projectiles in a clash last week that left one demonstrator with a serious head injury. Police critics said officers had used excessive force and violated city policies on crowd control. 
 
 But late Wednesday, hundreds of police officers responded to the area just before midnight. They found that protesters - many covering their faces with bandanas, and some in gas masks - had started a massive trash fire at 16th and Broadway that sent flames 15 feet high. 
 
 Police said later that they were concerned that the flames endangered residents in the area along with the 500 or so people on the street. 
 
 Just after midnight, police ordered the crowd to disperse as an unlawful assembly. Soon, one officer on Broadway was struck on his face shield by a bottle, disorienting him. 
 
 Within a minute, officers launched flash-bang grenades and tear-gas canisters. Protesters scattered and a fire crew put out the blaze. 
 
 The crowd quickly regrouped and entered into a long standoff with officers on Broadway. Another confrontation happened at 16th Street and San Pablo Avenue, where police surrounded several dozen people and arrested them just before 1:30 a.m. 
 
 Several of those arrested spoke before they were taken away. Jonathan Yeh, 26, of Davis, said he had been in the wrong spot at the wrong time and had not heard a dispersal order. 
 
 "I did hear people throwing bottles and breaking windows," he said. 
 
 Morgan Ress, 30, of Oakland was watching the protest as an observer for the National Lawyers Guild. 
 
 "Police formed lines on both sides of us," Ress said. "I saw them beat anyone who ran and arrest anyone who stood still." 
 
 Derek Winslow, 26, of Oakland, was working as a medic. 
 
 "I was attempting to provide medical aid to someone who was injured," Winslow said. "I didn't know how close I was to the police line. I was knocked down (by police) and told not to move." 
 
 He conceded that he hadn't obeyed orders. 
 
 "They gave me an order to disperse and I did not leave," he said. 
 
 Police officials drew a contrast between Wednesday's march to the port by Occupy Oakland protesters - which involved thousands of people and was peaceful - and the nighttime events, in which a much smaller crowd grew unruly. 
 
 They said the late-night protesters had thrown threw metal pipes, hammers, glass bottles, rocks and cobblestones. 
 
 "This begged action," said Sgt. Chris Bolton, chief of staff to interim Police Chief Howard Jordan. "We are reacting to the situation provided to us." 
 
 Many protesters disagreed, saying police had escalated the situation and should not have used tear gas. During the standoff, people shouted "go home" at the officers, who appeared to be from several Bay Area agencies. 
 
 "These people would be extremely peaceful if the agitators - the police - didn't show up," said a 25-year-old man in a bandana who declined to give his name. 
 
 He said the protesters' late-night actions had been "tactical. In other words, it was to make it bigger. There's an awe factor." 
 
 The protesters who were on hand for the clashes, though, were deeply split over what happened. Some scolded window-breakers and told them Occupy Oakland was supposed to be a peaceful protest. Whenever someone would light a fire, others would try to stomp it out. 
 
 "Violence is not a statement," one protester shouted after a man in a mask broke a clothing store window. 
 
 As protesters built one of the barricades on 16th Street, a nearby resident who had joined Wednesday's demonstrations walked up and began to take it apart. But whenever he moved a trash can or table or pallet, a man in a mask would put it back. 
 
 "What does putting trash in the street accomplish?" asked the neighbor, 35-year-old Tarrell Gamble, as a crowd confronted him. "This is somebody's property." 
 
 Masked men shouted and swore at Gamble, and one protester briefly put him in a headlock. They accused him of being a police officer and said, "Let's give it up for the hall monitor." 
 
 "Everybody's so tough with a mask on," Gamble said as he continued to try to clear his street, without success. 
 
 After two women escorted him away, Gamble said, "The protest is supposed to be about corporate greed. It's not about trashing the streets of Oakland." 
 
 Nearby, a man in a mask said Gamble was wrong. "These are drastic measures, to make people listen," the 24-year-old said. "This is our block now."
– What began as a largely peaceful protest in Oakland ended up being marked by the following: shattered windows, graffiti, fires, tear gas, flash-bang grenades, stitches, and arrests. Things didn't get ugly until after midnight, reports the San Francisco Chronicle. Most of the day's approximately 7,000 protesters headed home around 11pm, but a remaining group overtook an empty building two blocks from Occupy Oakland's tent city. They reportedly barricaded both ends of the block the building sits on; started a massive fire whose flames reached heights of 15 feet; hung banners from its roof; and graffitied its exterior. Police told the crowd to disperse and fired flash-bang grenades and tear gas canisters after an officer was reportedly hit with a bottle. They say protesters threw metal pipes, hammers, molotov cocktails, and more. The AP reports that at least four protesters were hospitalized, with one, who tussled with a cop, needing stitches. "Dozens" were arrested.