The NYPD may be using a military-grade sound cannon to disperse civil rights protesters, according to demonstrators.

Video surfaced on YouTube Saturday night showing that the NYPD appeared to be using a sonic device to disperse protestors rallying against a Staten Island grand jury's decision not to indict Eric Garner's killer.

An eyewitness said the sound cannon was used after glass bottles were thrown at the officers following police attempts to arrest protesters. The incident occurred near the corner of 57th Street and Madison Avenue.


The cannon is believe to be a long range acoustic hailing device (LRAD), used by the military and law enforcement to disorient and disperse demonstrators. The device was used against Occupy Wall Street demonstrators in 2011.

Manufactured by LRAD Corp, it's described on the official website as providing "military personnel with a powerful, penetrating warning tone that can be followed by clear voice broadcasts."

"You need to give people the opportunity to leave the area on their own accord before resorting to these types of tactics," Amnesty International researcher Justin Mazzola told Metro.

The NYPD did not respond to Metro's request for confirmation prior to deadline.

"Used at close range and at loud volume for an excessive length of time, [LRADs] can pose a serious health risk which can range from temporary pain and loss of balance and ear-drum rupture to permanent hearing damage," Mazzola said.

Protests are said to continue every night this week, leading up to the Millions March this Saturday. More than 34,000 are expected to participate.