One of New York’s Finest was caught on video smashing a teen’s bike in the South Bronx on Sunday — yet another instance of police harassment of cyclists, especially young bikers of color, and a clear abuse of trust and authority, according to another biker who was there and posted a video of the vicious attack on social media.

“Yo wtf is this NYPD cop doing to his bike like your job description is to protect and serve that’s it STOP ABUSING YOUR POWER,” the biker, who identified himself as Q the Biker, wrote on his Instagram account, Qdabikerspam. The original video was taken by Instagram user Russbushay.

The 17-year-old whose bike was smashed, who asked to be identified only as Devon, said that he and five friends were riding their bikes in a parking lot near the Bronx Terminal Market at about 3 pm when one of the men in blue told them to beat it because it’s private property.

The teen, who said he was riding his Framed Twenty9er BMX bike that day, was just hanging out outside the parking lot when the cop ran toward the group and started hitting the bike with an instrument resembling a baton, likely in an effort to stop the teens from pedaling off.

Instagrammer Russbushay started recording on his phone before the unidentifiable cop — who Devon said refused to give his name — starts pummeling Devon’s back wheels.

“We’re not doing nothing at all, we’re just sitting here relaxing, not bothering anybody, not riding back and forth no more. What else do you want from us?” he says in the video, which is also posted to YouTube.

All of a sudden, the cop starts whacking the teen’s bike’s spokes with one hand as he holds the other out to keep a kid off camera from stopping him.

“Yo what are you doing? What are you doing?” several people start yelling in the video, as three men in yellow shirts, likely officers from the private parking lot, watch from behind as the cop pummels the bike.

Devon says he plans to sue and is filing a formal complaint against police — repairs to fix his bike cost him $80, he said.

This is not the first time cops have targeted young bikers or have used force to stop them from moving. In April, more than 50 officers swarmed Tompkins Square Park and Union Square in order to harass kids on bikes and kick them out of the public spaces; police confiscated teens’ bikes and wrote tickets for bicycles that lacked bells.

Police Commissioner James O’Neill later acknowledged that he deployed his officers to hand out the tickets solely to stop what police thought would become an unruly bike ride. Bike advocates accused the de Blasio administration of “misplaced priorities and racist policies.”

“Just the latest example of Mayor de Blasio permitting and directing the NYPD to harass to cyclists of color. It’s a nouveau-Broken Windows style of policing under the guise of Vision Zero,” Transportation Alternatives’ Marco Conner said at the time.

In July, a cop pulled his SUV squad car in front of an earbud-wearing Citi Bike rider who had allegedly run two red lights and ignored an order to stop, forcing the man off his bike.

A cop who answered the phone at the 44th Precinct, which patrols the area including the Bronx Terminal Market, declined to answer any questions and referred Streetsblog to the Deputy Commissioner Public Information. Police did not immediately respond to a request for comment.