Wall Street protesters march in New York

media captionThe BBC's Laura Trevelyan reports from one of the demonstrations

Thousands of protesters have marched on New York's financial district, with rallies also held in other US cities.

Powerful unions gave a high-profile boost to the long-running demonstrations, as their members joined the rally in lower Manhattan.

Students at several US colleges walked out of classes in solidarity.

The activists have vented grievances over the 2008 corporate bailouts, high US unemployment and home repossessions, among other things.

Hundreds of demonstrators were arrested last weekend on the Brooklyn Bridge.

'Country upside down'

On Wednesday, smaller protests were held from Boston and Chicago to Los Angeles and San Francisco.

media captionThe Occupy Wall Street demonstrations are in their third week

The biggest event took place in New York, where at least 5,000 activists joined forces with members of unions and community organisations to march on Wall Street.

"Our workers are excited about this movement," United Federation of Teachers president Michael Mulgrew told Reuters news agency. "The country has been turned upside down. We are fighting for families and children."

The American Federation of State, County and Municipal Employees, Communications Workers of America and the Amalgamated Transit Union joined the New York march, as did the nation's largest union of nurses, National Nurses United.

The Occupy Wall Street protests started on 17 September 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 organised, lining up medical aid and legal help and printing their own newspaper.

Protesters in New York City on Wednesday carried signs reading "Jobs Not Cuts" and "Stop Corporate Greed" and chanted "Wall Street is our street".

"We're here to stop corporate greed," Mike Pellegrino, an NYC Transit bus mechanic, told the Associated Press news agency. "They should pay their fair share of taxes. We're just working and looking for decent lives for our families."

Hundreds of college students at New York's public university system walked out of classes on Wednesday afternoon.

At the University of Massachusetts at Amherst, students walked out of their classrooms at noon, holding signs reading "Eat the Elite" and "We Can Do Better than Capitalism".

'I'm the 99%'

In Boston, about 200 Northeastern University students protested against what they called corporate control of government and spiralling education costs.

image captionProtests in other US cities have attracted thousands of supporters

In San Francisco, a crowd of several hundred marched in a loop around the financial district, chanting "They got bailed out, we got sold out". Union nurses had a large presence at the protest.

In Chicago, dozens of activists kept up their protest at the heart of the financial district, banging drums and holding up signs.

Protests have also been held recently in the cities of Las Vegas, Baltimore, Philadelphia and Washington; and in the states of Missouri, Ohio and Florida.

MoveOn.org - a liberal activism website - is encouraging participants to post photos of themselves with the caption, "I'm the 99%" - a reference to those not among the wealthiest 1% of Americans.

The rallies have been largely peaceful apart from occasional scuffles, including the arrests of more than 700 protesters on the Brooklyn Bridge on Saturday.

Several Democratic lawmakers have expressed support for the protesters, but some Republican presidential candidates have lambasted them.

Herman Cain called the activists "jealous" and "un-American" on Wednesday at a book signing in Florida.

On Tuesday, former Massachusetts Governor Mitt Romney was quoted as calling the protest "class warfare" while campaigning in Florida.

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