Union Square Police Brutality Protest View Full Caption

UNION SQUARE — More than 100 people were arrested as thousands of people swarmed Union Square on Wednesday to decry the death of Freddie Gray, who died earlier this month from injuries he suffered in police custody in Baltimore.

Police posted signs ahead of the protest warning that anyone who blocked the road or sidewalk would be arrested for disorderly conduct.

An NYPD spokesman said Thursday morning that more than 100 people were arrested, but that he did not know the exact number.

Demonstrators broke out in chants of "black lives matter," but a police loudspeaker message that reinforced the posted signs drowned out the protesters.

Creepy #nypd msg amplified around union sq now saying blocking sidewalks/streets may result in arrest. & we haven't even begun. #ShutItDown — Sonny Singh (@brooklynsingh) April 29, 2015

Event organizers were eventually able to use their own speakers to address the crowd over the NYPD audio.

"Baltimore is not an isolated incident," Harlem resident Ahmad Greene, 20, told DNAinfo. "These are incidents that happen all the time."

Protests over Gray's death in Baltimore devolved into rioting in which several storefronts were looted and some buildings were set ablaze.

The Gray case is the latest in a series of nationwide protests after a number of unarmed black men have died while being arrested by police.

A group of protesters attempting to march in the street were arrested on East 17th Street shortly before 8 p.m.

Things getting tense on 15 st after police blocked protestors trying to march out of union square. Several arrests. pic.twitter.com/GWmRB76TDu — Ben Fractenberg (@fractenberg) April 29, 2015

Baltimore police were seen on April 19 in a cellphone video carrying Gray into the back of a police van while he screamed in pain.

He was not rushed to the hospital until after he arrived at the police station. After arriving at the hospital, he slipped into a coma and died several days later.