A refrain commonly chanted by Black Lives Matter activists was shouted Sunday night by St. Louis police officers as law enforcement officials arrested more than 80 people during the city’s third night of unrest.

“Whose streets? Our streets!” the cops yelled after clearing a street of protesters and spectators, according to The Associated Press.

The phrase was chanted twice, reported David Carson, a photographer for the St. Louis Post-Dispatch. He later tweeted that a police official claimed he hadn’t heard the chant but said he would “deal with it.”

It was chanted twice, AP journalists heard it too, I confirmed w/ 5x civilians standing closer to cops who chanted & with 2x cops at scene https://t.co/syuuAfi2bM — David Carson (@PDPJ) September 18, 2017

I spoke with the commander at the scene, he said he did not hear the chant, but said chant was not acceptable, said he would deal with it. — David Carson (@PDPJ) September 18, 2017

Carson also tweeted a video that he said captured police chanting the refrain.

Schron Y. Jackson, public information manager for the St. Louis Metropolitan Police Department, said the department is reviewing footage of “the video circulating on social media,” though she didn’t specify which video.

“We hold our officers to the highest standards of professionalism and any officer not meeting those standards will be held accountable,” Jackson told HuffPost in an email Monday.

The Ethical Society of Police, which primarily represents black St. Louis police officers, said such actions go against the oath officers take.

“We as officers took a sworn oath to uphold the mission, purpose, and goals of our Department toward our community, whether we encounter them in the street or in their homes,” President Heather Taylor told HuffPost in a statement.

“We must abide by that oath under all circumstances. Our Code of Ethics states, ‘I will never act officiously or permit personal feelings, prejudices, political beliefs, aspirations, animosities or friendships to influence my decisions.’ That chant goes against the very code of ethics we swore to abide by. Whether we agree with demonstrations, protests, or acts of violence, it is our job to do our job free of personal bias.”

Sunday marked the third night in a row that violence broke out in the city following peaceful daytime demonstrations protesting the acquittal of former St. Louis Police Officer Jason Stockley, 36, of first-degree murder in the 2011 shooting death of Anthony Lamar Smith, 24.

More than 1,000 people showed up to nonviolently protest police brutality, but by nightfall some people in the crowd had begun smashing storefront windows and vandalizing property. Police used pepper spray to disperse protesters and arrested those who did not follow their orders.

At least five weapons were confiscated from those arrested and some officers suffered “minor” or “moderate” injuries during the clashes, acting Police Commissioner Lawrence O’Toole said during a news conference early Monday.

O’Toole, who didn’t comment on the chanting, praised his officers for their “outstanding work” on Sunday night and proclaimed the “police owned the night.”

“I’m proud to tell you the city of St. Louis is safe,” O’Toole said during a news conference early Monday. “Once again, a group of criminals set out to break windows and destroy property. Tonight, those criminals are in jail.”

Michelle Higgins, co-chair of the St. Louis Action Council, said she was “unsurprised” by the officers’ attempt to “mock” protesters by chanting their own refrain back at them.

“It’s just a part of what seems like a cunning scheme to paint activists and protesters as the enemy,” Higgins told HuffPost. ”[O’Toole] has been very clear in prioritizing the possessions of city officials and the property of St. Louis over people.”

As protesters gathered again Monday morning for a silent, nonviolent march through the city, Missouri state Rep. Bruce Franks Jr. (D) responded to the reports of police chanting the previous night by describing a “new narrative.”

Thoughts from @brucefranksjr on the police saying "Who's streets, our streets" last night when arresting dozens downtown. pic.twitter.com/WE0CzuWbij — Ashley Jost (@ajost) September 18, 2017

“We are the system,” Franks Jr. told a reporter for the St. Louis Post-Dispatch. “We make up the system. We will affect your peace. We will make you uncomfortable. Peace is not an option ― nonviolence is.”

Jeffrey A. Mittman, the executive director of the ACLU of Missouri said in a statement that the weekend’s protests had been mostly peaceful and nonviolent, but the police department had continued to “engage in unacceptable, unlawful and unconstitutional behavior.” The organization is exploring legal options and encouraged people to ask themselves why the protests were happening.

“This region ― and our country as a whole ― have seen too many deaths caused by police, with little accountability for the officers or department involved. While many police officers act respectfully toward those they serve, we must acknowledge how regularly communities of color experience racial profiling and abuse from local law enforcement, including here in the St. Louis region,” he said.

This story has been updated to include comment from Michelle Higgins and the St. Louis Metropolitan Police Department public information manager.