A New York police officer captured on a smartphone video punching a black teenager during an arrest has been suspended, according to news reports.

The incident occurred Monday after police responded to a report of someone being assaulted with a cane and officers took two black youths into custody, according to CBS New York The charges against the youths were dropped before the video was released, according to the New York Daily News

As three unformed officers struggled to handcuff one of the youths, the video shows a fourth plainclothes officer — identified by the Daily News as John McDevitt of the 7th Precinct — running up from behind and delivering two blows to the teen’s backside, although it remains unclear whether he was resisting arrest. Several bystanders, including one who later identifies herself as a lawyer and asks for the officer’s badge number, yell at the officer to stop. Police identified the youth as 16-year-old Denzel Funderburk, according to CBS.

“An individual that we have identified as a plainclothes anti-crime officer runs up and appears to strike the individual with a closed fist twice on the side of the body,” New York Police Department Commissioner Bill Bratton told CBS New York. “That officer has been suspended pending the investigation going forward.”

Authorities made the announcement Friday.

The eight-minute video has racked up more than 600,000 views on YouTube  since it was posted Wednesday and comes amid heightened tensions between police departments and the public in cities across the country. In New York, dozens of marches protesting against police brutality have taken place since a Staten Island grand jury declined to indict New York police officer Daniel Pantaleo in the death of Eric Garner earlier this month.

“There doesn’t seem to be any legitimate reason for it,” police procedure expert Robert McRie, a professor at John Jay College, told CBS. “The arrestee was pinned up against the hood of a car, he wasn’t moving at the time the blows were delivered and he was in no position to escape.”

The individual who posted the video on YouTube wrote that the footage was taken on their way to the post office.

“They had supposedly pushed one of their classmates down,” the description says. “However when the victim was asked, he said those weren’t the guys. They were still taken away.”

The footage also shows a second youth, who onlookers tell police is a 12-year-old boy, being placed under arrest.

“You need to get a different profession,” a woman can be heard telling police after one of the boys groans in pain. “Go to war, this is not a war, this a 12-year-old kid.”

As he is led away in handcuffs, one of the youths be heard asking officers: “What did we do? Can I hear what we did?”