Thousands of Occupy Wall Street protesters marched across the Brooklyn Bridge Thursday after earlier clashes with police led to over 200 arrests on the two-month anniversary of the anti-capitalist movement.

The evening march, which took place without incident, was a show of force for the Occupy Wall Street campaign which has gone global, despite some recent setbacks including the clearing of the movement's home base in a New York park.

The New York protests were part of a "Global Day of Action" with hundreds of demonstrations planned across the United States. Police evicted protesters in Los Angeles and Dallas, arresting dozens of people.

In London, protesters refused to budge as a deadline to leave their camp outside St Paul's Cathedral by 1800 GMT passed, with the City of London Corporation now expected to start legal action to remove them.

Thousands also marched in Spain and Athens to protest austerity measures and public spending cuts, although the demonstrations were not directly linked to the OWS movement.

"We are unstoppable! Another world is possible!" chanted the crowd on the Brooklyn Bridge, which organizers said was 20,000 strong. New York police refused to offer a crowd estimate.

Union activists and students joined the movement's hardened members for the march, which was kept to the bridge's pedestrian walkway -- allowing evening rush hour traffic to proceed unhindered under the watchful eye of police.

Trucks and cars honked their horns in support of the demonstrators, who carried small electric candles in a festive atmosphere.

"Economic disparity has become worse and worse and we're becoming a third world country. The people who have the most are not paying their fair share," said 72-year-old Helen Engehardt.

"The people who turned Wall Street into Las Vegas are not being held accountable. But people are waking up."

Protesters staged an impromptu party in Brooklyn after the march.

The feel-good evening came after a day of acrimony between protesters and police outside the New York Stock Exchange, where clashes led to "over 200" arrests, according to a New York Police Department spokesman.

Chanting "Wall Street's closed!" "We are the 99 percent" and "Whose street? Our street!" about 1,000 demonstrators engaged in a tense face-off with hundreds of police, including many on horseback outside the iconic exchange.

While the stock market opened on time at 9:30 am (1430 GMT), protesters managed a 45-minute blockade outside the NYSE. Police eventually intervened to break through, establishing a corridor to escort traders and workers.

Amid the chaos, police then moved in to clear the street, and ensuing clashes sent police and protesters clattering to the ground. One man was repeatedly clubbed with a police baton, while several protesters were handcuffed and dragged into police trucks.

NYPD commissioner Ray Kelly said seven police officers had been hurt in the morning clashes.

Later, up to 2,000 people regrouped in Zuccotti Park, the symbolic heart of the movement where the Occupy camp was dismantled by police in a nighttime raid early Tuesday.

"We need to show we are bigger than Zuccotti Park, that we are resilient, that we refuse to submit to brutal police tactics," said Jessica Lingel, 28, a librarian from New Jersey.

At least one exasperated New York cop seemed to concede victory to the protesters, who launched their movement exactly two months ago to denounce corporate greed and the world's wealthiest "one percent."

"They've blocked everything off. This is what happens when you kick them out of the park: you stir a hornet's nest," said the officer who would not provide his name. "They wanted to disrupt Wall Street, and they've done it."

In Washington, more than 200 protesters marched under police escort from the Occupy DC encampment, near the White House, for the Francis Scott Key Bridge over the Potomac River, marching through the heart of the US capital.

In Chicago, thousands of protesters blocked rush hour traffic as they marched past financial institutions to a rally in front of the Chicago Board of Trade, chanting "Banks got bailed out! We got sold out!"

On the West Coast, more than 20 people were arrested after a morning sit-in at a major downtown intersection in Los Angeles. Police in Portland, Oregon said 34 people had been arrested during the day.

More than 460 protests were planned across the country, according to activist group MoveOn.