Update, Thursday, 10:30 a.m.:

The demonstrations turned violent Wednesday evening, with reports that officers used batons and mace against protesters. Read a report on the clashes here.

Original post:

These are not the few bedraggled Occupy Wall Street protesters we knew in September.

Representatives from some of the most powerful labor unions in the country have arrived to march alongside the protesters, and students from New York universities joined the demonstrations this afternoon.

(To see live updates click here.)

The protests today — which were expected to be the largest yet — began at 3 p.m. Eastern, when protesters in Zuccotti Square marched a mile north to Foley Square, met community and labor leaders, and then marched back at 4:30 p.m. The march was largely peaceful, and metal barriers and police kept the demonstrations from blocking traffic.

Many protesters carried signs or joined in chants about economic injustice, including: “Wall St. can't you see we want a fair economy!”

The reinforcements have added both size and credibility to the movement, which began Sept. 17 with a few dozen camped-out college students, and has voiced opposition against everything from corporate greed and bank foreclosures to the wars in Iraq and Afghanistan and unemployment.

Among the labor unions that marched today are representatives of the Chinatown Tenants Union, the Transit Workers Union, MoveOn.org, Working Families Party, United NY. See a full list here.

The first union to throw support behind the protesters was Transport Workers Union Local 100. Alexander Hotz and Alice Brennan from The New York World asked members of the TWU what inspired them to join:

Students from ColumbiaThe New School, and NYU also walked out of their classes and marched to City Hall, before joining community and labor leaders in the protests.

Tevor Roulstin, center, 25, from Durango, Colo., stands with a sign at the Occupy Wall Street Protest as police confer on Wednesday at Zuccotti Park in New York. (Bebeto Matthews/AP)

“i am a 19 year old student with 18 credit hours and 2 part time jobs. i am over 4000 dollars in debt but my paychecks are just enough to get me to school and back. next year my plan was to attend a 4 year college and get my bfa, but now i am afraid that without a co-signer i will have no shot at a loan and even if i can get a loan i am afraid that i will leave college with no future and a crippling debt.”

The blog, despite its grainy photos and calls for help — or perhaps in spite of them — has also given the movement a sense of legitimacy.

The movement has also spread to cities like Los Angeles, Chicago, and Washington. Gathering in McPherson Square in Washington this weekend, protesters told the Post they did not have a specific goal in mind:

As the movement continues to grow, politicians and celebrities alike have come out in support of the protesters.

Federal Reserve Chairman Ben Bernanke told the Joint Economic Committee Tuesday that he understands the protesters' frustrations.

“I would just say very generally, I think people are quite unhappy with the state of the economy and what’s happening,” Bernanke said. “They blame, with some justification, the problems in the financial sector for getting us into this mess, and they’re dissatisfied with the policy response here in Washington. And at some level, I can’t blame them.”

Some protesters want to “End the Fed,” anyway:

This weekend, protesters were buoyed by a rumor that the band Radiohead would appear to play and support them. While the rumor turned out to be false, indie band Neutral Milk Hotel’s Jeff Mangum showed up instead and sang eight songs for the protesters:

The protests have also garnered support from Lupe Fiasco, Michael Moore, Noam Chomsky, Russ Feingold, and former White House adviser Van Jones, who suggested that the Wall Street protesters were the tea party-like movement liberals needed right now.

Occupy Wall Street is also being supported by hacktivist group Anonymous, which attacked a number of corporate and government Web sites this year. According to a video message posted on YouTube, Anonymous says it will support the protesters by erasing the New York Stock Exchange “from the Internet” on Oct. 10.

Below, follow live updates from the scene: