Cops made multiple arrests Monday afternoon when a Ferguson-related protest disrupted traffic around Union Square, the NYPD said.

The demonstration was among dozens planned nationwide to protest a grand jury’s decision last week to clear white cop Darren Wilson in the fatal shooting of unarmed black teen Michael Brown in Ferguson, Mo.

Photos posted on Twitter show dozens of activists holding signs and marching in the street, followed by NYPD cops wearing riot helmets and carrying batons and plastic handcuffs.

It was unclear how many people were busted or the charges against them.

The CAAAV, an Asian-immigrant advocacy group, claimed more than 1,000 people took part in the protest and posted a photo of a large group of teens it said were high school students cutting class so they could march.

Photos posted by other Twitter users also showed protesters lying on the ground outside the Department of Justice headquarters in Washington, DC, and blocking traffic at Harvard Square in Cambridge, Mass.

The “Ferguson Action” group had urged students and workers to leave their schools and jobs with their hands in the air to symbolize witness accounts of how Brown was posed when he got killed.

The “Hands Up Walk Out” was called for 1 p.m. New York time.