At least a dozen Occupy Wall Street protesters were arrested yesterday evening during a march from Washington Square Park to Zuccotti Park, as police repeatedly "plunged" into the group to detain people on the sidewalk. An NYPD spokesman refused to confirm the number of arrests—the Times estimates 15, while the NLG believes the number to be as high as 25.

Colin Moynihan observed ranking NYPD officers in white shirts throwing people into the sidewalk, and noted that police were singling protesters out, seemingly at random, to be arrested. The tactic is a hallmark of the NYPD's policing of Occupy Wall Street demonstrations, both large and small.

Here's footage of several arrests taken by videographer Tim Pool.

The day began peacefully in Washington Square Park, as several hundred protesters congregated to mark the beginning of the movement's one-year anniversary. Demonstrators listened patiently as events and meetups were announced through the People's Mic, before separating into break-out groups to concentrate on a specific issue. Notable members of the movement, like Bishop George Packard and former Philadelphia Police Captain Ray Lewis strolled alongside the protesters, many of whom were continuing to arrive from out of town.

Today's events (the only ones of the weekend that possess a permit) begin in Foley Square at 1 p.m. with a long lineup of musicians and performers, including Jello Biafra, Tom Morello, Rebel Diaz, and Lee Ranaldo of Sonic Youth. There will also be direct action training in preparation for tomorrow's robust schedule of targeted protests designed to shut down Wall Street.