Brnovich said Tuscon’s vaccine mandate violated newly passed state legislation that prohibits local governments from implementing vaccine requirements for employees. He also cited an executive order implemented by Republican Governor Doug Ducey in August, which further outlaws coronavirus vaccine mandates.

“Tucson’s vaccine mandate is illegal, and the city could be held liable for attempting to force employees to take it against their beliefs,” Brnovich said in a statement. “COVID-19 vaccinations should be a choice, not a government mandate.”

Brnovich’s office said the city of Tuscon has been notified of its decision, and that it will now have 30 days to retract the order. If it does not comply, the office said it will notify the Arizona treasurer and withhold Tuscon’s portion of state shared revenue.

The latest ruling comes amid repeated clashes between Democratic-led Tuscon and Arizona’s conservative government.

Last month, Tuscon mandated that all city employees must receive a first vaccine dose by August 24 or face a five-day suspension from work without pay. The policy also included an incentive for vaccinated employees to receive extra time off and allowed the city to charge higher health insurance premiums for unvaccinated workers.

“The decision not to get vaccinated unjustly exposes others to the risk of illness, including co-workers and members of the public,” Tuscon Mayor Regina Romero said last month. “It puts children under the age of 12, who are not eligible to receive the vaccine, at an increased rate of exposure to COVID-19.”

The decision to strike down the mandate on Tuesday came weeks after a complaint was filed by Republican Senator Kelly Townsend, who has been one of the legislature’s most vocal critics of pandemic restrictions, according to the AP. Under a 2016 law, any lawmaker can request the attorney general to investigate whether a local ordinance or policy violates state laws.

In its announcement on Tuesday, Brnovich’s office said that while private businesses can require employees or customers to be vaccinated against COVID-19, government agencies are prohibited from doing so.

In a statement shared with Newsweek Tuesday, Romero called the decision “deeply disappointing” and said the city is reviewing options regarding how it will proceed.

“It is deeply unfortunate, but not surprising, that the Attorney General is prioritizing his political ambitions over his responsibility to objectively interpret the law,” Romero said. “This report reads more as a campaign speech filled with political commentary rather than a fact-based legal opinion. We are currently reviewing our options, and Mayor and Council will need to provide direction as to how we proceed from here.”

Tuscon City Manager Michael Ortega added that while the city assesses its legal position, the vaccine mandate will be halted.

“I believe that the City vaccine policy is an important and necessary step to protect our staff and the community,” Ortega said. “Until we have a better understanding of our legal position in relation to today’s report, I have instructed staff to pause on the implementation of the policy.”

Update 9/7/21 6:15 p.m. ET: This story has been updated with a comment from Mayor Romero’s office.