* Movement inspires rallies in numerous cities
* "Anarchists" wear black bandannas in some locations
* Packets of harmless white powder mailed to N.Y. banks
By Atossa Araxia Abrahamian and Emmett Berg
NEW YORK/OAKLAND, Calif., May 1 (Reuters) - Occupy Wall Street protesters smashed windows in Seattle, were chased through New York streets by police on scooters, and clashed with officers in Oakland on Tuesday in May Day demonstrations intended to revive their movement against economic injustice.
While many events involving thousands of protesters were peaceful or even festive and few injuries were reported, dozens of people were arrested at rallies across the country, including more than 30 in New York during a series of skirmishes throughout the day.
In Oakland, police in riot gear fired tear gas and flash-bang grenades to disperse protesters who they said threw objects at officers and struck them with corrugated metal shields. City officials said marchers also vandalized two banks, a police van and a news vehicle. Nine were arrested.
"I was standing on the outside and the cops came in, snatched two people in the crowd, beat them and put them in the paddy wagon," Occupy Oakland organizer Caitlin Manning said.
Much of the violence and vandalism was attributed to black-clad anarchist elements within the Occupy movement who have been involved in previous confrontations with police, marring what began as a peaceful anti-Wall Street protest movement.
But the clashes they helped spark last year had also served to inject new life into the protests as demonstrators took up the issue of police brutality following running clashes in Oakland and pepper spray incidents elsewhere in the country.
In downtown Seattle, protesters carrying black flags on sticks shattered the windows of several stores including a Nike Town outlet and an HSBC bank before police moved them out of the area. Others smashed windows at a Seattle federal building, and several were taken into custody.
Inspired by the Arab Spring, the Occupy Wall Street movement captured world attention last year with a campaign decrying the gap between rich and poor and a political system and tax structured tilted toward the wealthiest 1 percent.
'YOU ARE NOT IN CONTROL'
In New York, where the Occupy movement began last September, thousands packed New York's Union Square in a party-like atmosphere with Rage Against the Machine guitarist Tom Morello.
"It's definitely a restart for Occupy Wall Street," said Lily Schwarzbaum, 21, who is from New York but studies in Montreal, Canada. "Occupy Wall Street has been very conscious of making it a kick-off."
But before the day was out, about 400 New York protesters - many wearing black clothes and bandannas - ran onto Broadway as police chased them on scooters.
Police also reported 10 instances of harmless white powder -- apparently meant to raise an anthrax scare -- being mailed to financial institutions and others, along with notes saying, "Happy May Day ... This is a reminder you are not in control."
David Meyer, sociology professor at the University of California, Irvine, said the movement needed to rein in its more radical elements if it wanted to retain support by the American public.
"The challenge is that the most radical action, particularly if it's violent, is going to get the most attention," Meyer said. "The broader Occupy movement runs the risk of being discredited by its own radical flank."
In that vein, Occupy Cleveland canceled its events "out of respect for the city" after five self-described anarchists were arrested on suspicion of plotting to blow up a four-lane highway bridge over a national park.
Occupy Cleveland said in a statement the men arrested were associated with their movement but that "they were in no way representing or acting on behalf of Occupy Cleveland." The group said it was committed to non-violent protest.
OFFICER HURT IN LOS ANGELES
Although labor unions rejected pleas from leaders of the Occupy movement for a general strike, forcing demonstrators to abandon a plan to shut down San Francisco's Golden Gate Bridge, activists hailed the day's events as a step forward for a movement that had grown inactive and cash poor since capturing world attention last fall.
"We've been building important alliances and radicalized people in what they're willing to endorse. I mean, we never even used to celebrate May Day. Now look at this," said David Graeber, an anthropologist and author active in the movement.
May Day, also known as International Workers' Day, has long been a day on which the labor movement holds street demonstrations and marches, but less so in the United States than elsewhere around the world.
In Los Angeles, thousands of protesters including a large contingent of immigrant rights activists, some waving Mexican flags, marched through the downtown financial district, remaining mostly peaceful despite a few minor skirmishes.
American Apparel CEO Dov Charney, who took part in the rally, said he gave some 200 workers at the company's downtown Los Angeles factory the afternoon off to participate.
"We want to support a non-apartheid system," Charney told Reuters, referring to U.S. immigration policies.
Lieutenant Andy Neiman, a spokesman for the Los Angeles police department, said a female police officer was struck by a skateboard during a scuffle with protesters and was taken to a local hospital, where she was listed in stable condition.
Ten people were arrested near Los Angeles International Airport after they blocked a major thoroughfare.
In Portland, about a dozen people were arrested after clashing with police during a downtown march.