On Tuesday evening, thousands of demonstrators launched a series of anti-police protests in many of the country’s biggest cities, but dozens of protesters were arrested after some marchers turned violent.

The most violence occurred during the protests in New York City, where some three dozen protesters were detained by New York police.

The Big Apple march was sponsored by the Stop Mass Incarceration Network and began at 2PM in Union Square. The protest kicked off with a reading of names of New Yorkers killed by police.

The violence began as police blockaded protesters near NYPD HQ in Lower Manhattan. The marchers quickly broke through barriers and flooded onto the Brooklyn Bridge in an effort to hold up traffic during rush hour. Many arrests were made on the bridge.

Marchers continued through downtown Brooklyn, blocking traffic and harassing pedestrians. More arrests were made in these areas, too.

The NYPD also reported that two officers were assaulted during the protests.

But New York wasn’t the only place where anti-cop protests got out of hand. Police in Los Angeles also arrested more than a dozen protesters.

In LA protesters ignored police warnings not to attempt to disrupt the Metro Rail as protesters streamed onto the tracks. Some arrests resulted when protesters tried to get on the tracks anyway.

In San Francisco about six protesters were arrested for running onto an offramp near Fourth Street and then onto eastbound Interstate 80 on the Bay Bridge. The marchers blocked traffic lanes for a short time.

By comparison, Chicago’s protests were mild, with only two arrests being made.

Follow Warner Todd Huston on Twitter @warnerthuston or email the author at igcolonel@hotmail.com