"I'll kill you!" a cop can be heard in the video. "I'll f------ kill you! What did I tell you guys? What did I tell you?"
The cop then appears to push one of the men onto a sidewalk. Another cop can be seen shoving protesters.
"While the tape shows a chaotic scene, nothing on it remotely justifies a threat to kill protesters and nothing justifies repeated hitting," Christopher Dunn, the New York Civil Liberties Union's associate legal director, said. "This is a blatant example of excessive force and the NYPD should investigate."