Chicago Mayor Lori Lightfoot (D) spoke out on Monday to say that there will “absolutely” be a COVID-19 vaccine mandate for city employees.

“We absolutely have to have a vaccine mandate. It’s for the safety of all involved, particularly members of the public who are interacting with city employees on a daily basis. It’s important for colleagues to also feel like they have a workplace that is safe,” Lightfoot said, according to The Chicago Sun Times.

“City employees are absolutely gonna be required to be vaccinated,” she added. “We’re working through those discussions, which have been ongoing now for a couple of weeks with our colleagues in organized labor that represent city employees.”

This came hours after the U.S. Food and Drug Administration fully approved the Pfizer-BioNTech vaccine. Chicago Federation of Labor President Bob Reiter told The Sun Times that “Discussions around COVID-19 vaccinations are ongoing with the city.”

“Any specific policy should be informed by the city workforce,” he added. “We look forward to continuing those discussions.”

Fraternal Order of Police President John Catanzara, whose union represents rank-and-file Chicago police officer, fired back by saying that vaccine mandates should not be allowed.

“It cannot be mandated. It’s that simple. Our members don’t want to be mandated to do anything like that,” Catanzara said. “This vaccine has no studies for long-term side effects or consequences. None. To mandate anybody to get that vaccine, without that data as a baseline, amongst other issues, is a ‘Hell, no’ for us.”

Lightfoot was also asked by reporters about city plans for booster shots.

“In the short-term, don’t believe that we will need to stand up the huge vaccination sites that we’ve seen before,” she said. “But a lot of that is gonna depend on what the final CDC guidance is and, obviously, making sure that we’ve got logistical and other resources support.”

In the meantime, Lightfoot said that her focus is on convincing unvaccinated Chicagoans to get the shot.

“When we see that well over 97% of the people who are showing up in hospitals and ending up in ICU beds or worse — and there have been deaths — are among the unvaccinated, we know that there’s a lot more work to be done,” she said, adding that six to eight city ZIP codes, “primarily” on the South Side, have vaccination rates of “30% or less.”

“If we raise the percentage by neighborhood, by ZIP code who are vaccinated, then we’re gonna go a long way toward starting to see the pandemic in the rear view mirror,” Lightfoot said. “But where we’ve got numbers like that in certain ZIP codes … we’ve got work to do. … We’ve just got to keep pushing more and more people who are on the fence, who aren’t vaccinated, to get vaccinated.”