Several New York City police officers were attacked and injured Wednesday as pro-police and anti-police protesters clashed on the Brooklyn Bridge.

At least four officers were hurt, including Chief of Department Terence Monahan, and 37 people were arrested, police said. Information on charges was not immediately available.

Surveillance video posted on social media by the police department showed a man on the bridge’s pedestrian walkway rushing toward a group of officers and reaching over a fence to bash their heads with a cane.

Police photos of the aftermath showed a lieutenant with a bloodied face, a detective holding a bandage to his head, and a bicycle officer helping a fellow officer dress a head wound.

Monahan, who last month knelt in a show of solidarity with protesters, sustained injuries to his hand.

He and the other injured officers were marching with a pro-police group led by local clergy when they were met on the bridge by anti-police activists, some of whom have been camping outside City Hall in recent weeks to demand severe cuts to police funding.

Some people in the pro-police group marched with a banner that said, “We Support the NYPD." The leader of that group said they were calling for an end to a recent spate of violence, including the shooting death of a 1-year-old boy in Brooklyn.

Wednesday's demonstrations were the latest in a wave of protest activity across the country since George Floyd was killed May 25 by Minneapolis police.

The first few nights of protests in New York City were marred by stealing, unrest and violence inflicted both by and on police officers. Since then, protests have largely been peaceful.

(Copyright 2020 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed without permission.)