Two police officers in Buffalo, New York, have been charged with assault after a video showed them shoving a 75-year-old protester to the floor.

The elderly gentleman had been attending a recent demonstration on Thursday evening, protesting the death of George Floyd.

Robert McCabe and Aaron Torgalski, who surrendered Saturday morning, pleaded not guilty to second-degree assault, and were released without bail.

Aaron Torgalski (left) and Robert McCabe (right) have been charged with assault. Credit: AP

The footage shows a man identified as Martin Gugino approaching a line of helmeted officers holding batons as they clear demonstrators from Niagara Square around the time of an 8pm curfew.

Two officers push Gugino backward, and he hits his head on the pavement. Blood spills as officers walk past. One officer leans down to check on the injured man before another officer urges the colleague to keep walking.

Local media reported two medics came forward and treated the man who was taken away in an ambulance. His current condition is unknown.

District Attorney John Flynn said the officers “crossed a line". The officers have been suspended without pay Friday after a TV crew captured the confrontation near the end of protests.

Protests have been sparked across the world following the death of George Floyd. Credit: AP

The video of the encounter sparked outrage online as demonstrators take to cities across the country to protest Floyd’s death.

Governor Andrew Cuomo said at a press briefing on Saturday: “I think there was criminal liability from what I saw on the video.

“I think what the mayor did and the district attorney did was right, and I applaud them for acting as quickly as they did.”

He added: “What we saw was horrendous and disgusting, and I believe, illegal."

But dozens of Buffalo police officers who were angered over their fellow officers’ suspensions stepped down from the department’s crowd control unit Friday. The resigning officers did not leave their jobs altogether.