CHICAGO (CBS) — Mayor Lori Lightfoot offered an apology, of sorts, after she was caught on a live microphone calling a Fraternal Order of Police vice president a “clown” during the public comment period of Wednesday’s City Council meeting.

“I’m sorry that I said it out loud,” she said.

As CBS 2’s Vince Gerasole reported Wednesday evening, the mayor and business and labor leaders were glowing over their cooperation on some considerable progressive legislation they tackled together. But in the middle of their huddle, Lightfoot’s comments were caught on an open microphone – and showed how tough and opinionated the mayor can be.

Lightfoot ran a tight ship during the City Council meeting. She did not go easy on one speaker, who published reports said attended on behalf of 75 murdered South Side women and claimed those murders have never been investigated by police.

“Don’t ever, ever tell me what to do when I’m standing here conducting the business of the people,” she said to the man. “Do you understand that, sir?”

But it was Lightfoot’s whispered comments that made the headlines.

The mayor’s insult was caught by a microphone on a Facebook video live-streaming Wednesday’s meeting as FOP Vice President Pat Murray was walking up to speak to the mayor and aldermen at the start of the meeting.

“Oh, back again,” Lightfoot whispered from her seat on the dais in the City Council chamber. “This is this FOP clown.”

After the meeting was over, reporters made Lightfoot aware of the gaffe. She said, “It was not appropriate for me to say that out loud.”

The FOP was quick to call Lightfoot’s apology into doubt.

In an email, FOP spokesman Martin Preib called the mayor’s “clown” remark “a misguided and dangerous thing to say to a 30-year veteran police officer and FOP representative, particularly at a time when the city is facing such chronic violent crime.”

“It is also telling that the Mayor would not even apologize. The red noses, however, belong on the members of the Chicago Police Board, her former agency, for their despicable decision to fire three police officers and a sergeant last week for no good reason whatsoever,” he added.

Lightfoot sparred with Murray at the previous City Council meeting last month, when he said the mayor should be seeking input from the union representing rank-and-file police officers as she seeks to reform the department.

“What you failed to do, mayor, is you failed to take and ask the FOP for our input,” he said.

Lightfoot didn’t waste any time firing back, accusing the FOP of opposing any reforms.

“Anytime that the FOP wants to do anything other than obstruct and object to reform, I’d be more than willing to meet with you,” she said.

Murray, who clearly did not hear the mayor’s “clown” remark at the time she made it on Wednesday, spoke at the City Council meeting to criticize the Chicago Police Board for firing four officers for covering up for Officer Jason Van Dyke after he fatally shot Laquan McDonald in 2014.

He accused former Mayor Rahm Emanuel’s office of covering up the fatal shooting by keeping dashboard camera video of the shooting, and said the officers who were fired did their jobs the night of the shooting by responding to a threat posed by McDonald.

“The problems that occurred with this case occurred on the 5th Floor [of City Hall]. They were concealed from the beginning, and just made this worse and worse, and these officers took the brunt of it. They did their jobs,” “Nobody worked together to form a conspiracy.”

Murray said the police union would fight to reverse the Police Board’s decision to fire the officers by taking their case to court.

“These officers did nothing wrong,” he said.