Mayor of Chicago Lori Lightfoot has spoken out over a video of a police officer shouting an anti-gay slur at Black Lives Matter protesters in the city.

A clip emerged on social media last week of the unnamed officer, dressed in a Chicago Police Department uniform, snapping back at protesters after a projectile is thrown.

The officer, who does not appear to be injured, yells at the protesters: “B***h! Wait ’till I turn my back, you f**king faggot!”

An investigation is now underway after the incident was reported to Chicago Police.

Mayor Lori Lightfoot: Homophobic comments ‘demean the value of who we are as Chicagoans’.

Mayor Lori Lightfoot — one of the first out queer Black women in officeanywhere in the United States — told a press conference on June 5: “We will not tolerate people who cross this line. We will not tolerate excessive force.

“We will not tolerate profanity and homophobic comments that demean the badge, demean the honour of being a Chicago police officer, and demean the value of who we are as Chicagoans. We will not tolerate that.

“If you are one of those officers who choose to do those things, or to tape over their badges, or to turn off their body-worn cameras — all things that violate very clear directives of the Chicago Police Department — we will find you, we will identify you, and we will strip you of your police powers. Period.

“We are not going to tolerate this in our city.”

The mayor added: “If you believe a police officer has committed an act of misconduct, please call 311 to report it.”

Chicago Police Department says it is investigating ‘unacceptable’ behaviour.

The Chicago Police Department said in a statement: “A complaint of misconduct has been received regarding this incident, and we immediately opened an investigation, which is now underway.

“The Chicago Police Department strives to treat all individuals our officers encounter with respect. Any derogatory conduct is inexcusable and has no place in the Department.

“We do not tolerate this kind of behaviour, which is why we have opened an investigation into this incident and will take appropriate disciplinary action immediately as we work to identify the officer involved.

“Anyone who feels they have been mistreated by a CPD officer is encouraged to call 311 and file a complaint with COPA, who will investigate allegations of misconduct.”