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Protests on Wall Street turned violent Wednesday when police clashed with demonstrators marching through Lower Manhattan in the largest show of strength yet for the Occupy Wall Street movement.

Police said late Wednesday that 28 people were arrested during the march, mostly for disorderly conduct, the New York Post reports. One police officer suffered minor injuries after being knocked off a scooter, according to the newspaper.

At one point, protesters were reportedly Maced and threatened with police batons when about 150 marchers demanded access to Wall Street from Broadway.

The protests against corporate America are expected to spread to New Jersey on Thursday as a show of solidarity with demonstrations that started last month outside the New York Stock Exchange.

Rallies are planned at the Statehouse in Trenton and in Jersey City. Protesters are expected to call for an end of corporate control of government, starting at 2 p.m.

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The initial protests in New York City, called Occupy Wall Street, started Sept. 17 and have since spread to other cities.

In Los Angeles, police have begun arresting a group of anti-Wall Street demonstrators who entered a Bank of America during a downtown march by hundreds of protesters.

The Thursday afternoon march through the financial district has been peaceful but police formed containment lines when the demonstrators filled an intersection.

One small group split away and entered the bank, leading to a handful of arrests.

Demonstrators have also been camping out at Los Angeles City Hall for the past week and say they may continue to do so through the winter.

Unions loaned their muscle to the rallies against Wall Street and economic inequality Wednesday, fueling speculation about how long the camp-out in lower Manhattan -- and related demonstrations around the country -- will continue.

Thousands of protesters, including many in union T-shirts, filled lower Manhattan's Foley Square on Wednesday and then marched to Zuccotti Park. Labor leaders say they will continue to support the protests, both with manpower and donations of goods and services.

"The great thing about Occupy Wall Street is that they have brought the focus of the entire country on the middle-class majority," said George Aldro, 62, a member of Local 2325 of the United Auto Workers, as he carried the union's blue flag over his shoulder through lower Manhattan.

"We're in it together, and we're in it for the long haul."

The protesters have varied causes, but have spoken largely about unemployment and economic inequality, reserving most of their criticism for Wall Street. "We are the 99 percent," they chanted, contrasting themselves with the wealthiest 1 percent of Americans.

Ed Figueroa, a janitor in a public school in the Bronx and a shop steward with Local 32BJ of the Service Employees International Union, said the march was "the first time in these weeks that unions have shown their face."

"But it won't be the last time," he said. "We'll be back."

The unions were donating food, blankets and office space to the protesters, said Dan Cantor, head of the Working Families Party. But he said the young protesters would continue to head their own efforts. The movement lacks an identified leader and decisions are made during group meetings.

"They're giving more to us than we're giving to them. They're a shot in the arm to everybody," Cantor said.

"The labor movement is following the youth of America today and that's a good thing."

Victor Rivera, a vice-president for the powerful 1199 Service Employees International Union, which represents health care workers, said the union had donated "all the food they need for this entire week" to the Zuccotti Park campers. Union leaders had also assigned liaisons from their political action committee to work with demonstrators.

"We are here to support this movement against Wall Street's greed," he said. "We support the idea that the rich should pay their fair share."

The Occupy Wall Street protests started Sept. 17 with a few dozen demonstrators who tried to pitch tents in front of the New York Stock Exchange. Since then, hundreds have set up camp nearby in Zuccotti Park and have become increasingly organized, lining up medical aid and legal help and printing their own newspaper.

On Saturday, about 700 people were arrested and given disorderly conduct summonses for spilling into the roadway of the Brooklyn Bridge despite warnings from police. A group of those arrested filed a lawsuit Tuesday, saying officers lured them into a trap before arresting them.

Several Democratic lawmakers have expressed support for the protesters, but some Republican presidential candidates have rebuked them. Herman Cain called the activists "un-American" Wednesday at a book signing in St. Petersburg, Fla.

"They're basically saying that somehow the government is supposed to take from those that have succeeded and give to those who want to protest," the former pizza-company executive said. "That's not the way America was built."

On Tuesday, CBS reported that former Massachusetts Gov. Mitt Romney called the protest "class warfare" at an appearance at a Florida retirement community.

Activists have been showing solidarity with the movement in many cities: Occupy Providence. Occupy Los Angeles. Occupy Boise. More protests and sit-ins are planned across the country in the days ahead.

On Wednesday, more than 100 people withstood an afternoon downpour in Idaho's capital to protest, including Judy Taylor, a retired property manager.

"I want change. I'm tired of things being taken away from those that need help," she said.

In Seattle, demonstrators tussled with police officers and clung to tents as they defied orders to leave a park. Police said they made 25 arrests. The reception was warmer in Los Angeles, where the City Council approved a resolution of support and Mayor Antonio Villaraigosa's office distributed 100 rain ponchos to activists at another days-long demonstration, according to City News Service.

In Boston, hundreds of nurses and Northeastern University students rallied together to condemn what they called corporate control of government and the spiraling costs of education. The students banged on drums made of water jugs and chanted, "Banks got bailed out, and we got sold out."

"This is an organic process. This is a process of grassroots people coming together. It's a beautiful thing," said David Schildmeier, spokesman for the Massachusetts Nurses Association.

Many of those protesting are college students. Hundreds walked out of classes in New York, some in a show of solidarity for the Wall Street movement but many more concerned with worries closer to home. Protests were scheduled at State University of New York campuses including Albany, Buffalo, Binghamton, New Paltz and Purchase.

Danielle Kingsbury, a 21-year-old senior from New Paltz, said she walked out of an American literature class to show support for some of her professors who she said have had their workloads increased because of budget cuts.

"The state of education in our country is ridiculous," said Kingsbury, who plans to teach. "The state doesn't care about it and we need to fight back about that."

Newscore and the Associated Press contributed to this report.