Wednesday night some of the protestors tried to move their demonstration to Wall Street.
The response from police was immediate.
NYPD officers used force.
One officer was swinging his baton and striking some of the protestors, while another officer aiming pepper spray at the crowd.
Police were working to clear Broadway by pushing protestors back and arresting some when they rushed the barricades.
Several protestors were loaded into police vans and headed for jail.
When questioned about police actions an NYPD spokesman responded: "They tried to storm the barricade."
Tension had been building between police and some of the protestors.
Protestors lined the sidewalks, chanting the slogans that for some have come to symbolize this two and a half week demonstration.
What was a peaceful protest turned violent and the confrontations continued into the night.
Protesters in suits and T-shirts with union slogans left work early Wednesday to march with activists who have been camped out in Zuccotti Park for days. Some marchers brought along their children, hoisting them onto their shoulders as they walked down Broadway.
"We're here to stop corporate greed," said Mike Pellegrino, an NYC Transit bus mechanic from Rye Brook. "They should pay their fair share of taxes. We're just working and looking for decent lives for our families."
Of the camping protesters, he said, "We feel kinship with them. We're both looking for the same things."
People gathered in front of the courthouses that encircle Foley Square, then marched to Zuccotti Park, where they refueled with snacks and hurriedly painted new signs as the strong scent of burning sage wafted through the plaza.
The protesters have varied causes but have spoken largely about unemployment and economic inequality and reserved most of their criticism for Wall Street. "We are the 99 percent," they chanted, contrasting themselves with the wealthiest 1 percent of Americans.
Susan Henoch, 63, of Manhattan said she was a "child of the `60s" and came out to the park for the first time Wednesday. She held a sign that read, "Enough."
"It's time for the people to speak up," she said. "Nobody's listening to us, nobody's representing us. Politics is dead.
"This is no longer a recognizable democracy. This is a disaster," she said.
Some of the union members traveled from other states to march.
Karen Higgins, a co-president of National Nurses United, came down with a group of colleagues from Boston. She said they had seen patients who skipped important medical tests because they couldn't afford them.
"Tax Wall Street," she said. "Those who make all the money need to start paying 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.
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 movement in many cities: Occupy Providence. Occupy Los Angeles. Occupy Boise.
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, at least four demonstrators who had been camping out since the weekend in a downtown park were arrested after they refused orders from city park rangers to pack up. The reception was warmer in Los Angeles, where the City Council approved a resolution of support and Mayor Antonia Villaraigosa's office distributed 100 rain ponchos to activists at another dayslong 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 their 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 grassroot 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."
Not every campus appeared to feel the rumblings of dissent. At the University of Michigan in Ann Arbor, there were students publicizing breast cancer awareness and National Coming Out Week, students crawling on their elbows in an apparent fraternity hazing ritual, quarreling evangelicals and even a flash mob to promote physical fitness, but no sign of the Wall Street protests.
Senior Alex Brown tried to promote an event on Facebook, but said students' disgust with the government and wealth inequality was "not enough to reach a fever pitch."
Some protesters were recent graduates looking for work, including Rachelle Suissa, who held up a sign in Manhattan that read: "I have a 4.0 GPA & $20,000 in debt. Where's my bailout?"
The 25-year-old Brooklyn woman said she has applied for at least 200 jobs and is finding it difficult to remain optimistic.
"I don't understand what's going on here," she said.
Associated Press writers Cristian Salazar and Karen Zraick in New York City, Mark Pratt in Boston, Chris Carola in New Paltz, N.Y., Tamara Lush in St. Petersburg, Fla., and Justin Pope in Ann Arbor, Mich., contributed to this report.