City attorney Brad Holm sent the letter on Thursday demanding Trump, his campaign and all of their affiliates and agents immediately take down the ad from every medium for its portrayal of active-duty Phoenix police officers in uniform and at work.
"Phoenix has not approved –- and will not approve -– the creation or use of any media bearing the faces and likeness of its on-duty police officers in any political advertisement for any political candidate," Holm wrote in the letter, obtained by ABC News.
The ad in question, titled "Movement," includes a short clip showing Phoenix police officers surrounding Trump. The Republican presidential nominee is seen shaking hands with one of the officers in the video. The ad began airing on Sept. 20.
In the letter to Trump’s campaign, Holm said the officers were unaware that they were being filmed and photographed, and they didn't give consent to the use of their on-duty images in a campaign advertisement for Trump or any other candidate. The issue extends beyond the officers, he said, because the Arizona capital has copyright over their uniforms, badges, insignia and all other imagery of official city materials and on-duty employees.
"In this context, the ad unmistakably and wrongfully suggests that Phoenix and the officers support or endorse Mr. Trump's campaign. That is not the case," the city attorney wrote. "The Phoenix City Manager has authorized me to pursue all legal remedies necessary to stop the Trump campaign from using the City's intellectual property."
City spokeswoman Julie Watters told ABC News today that they have not yet received a response from Trump’s campaign.
Trump's campaign also did not immediately respond to ABC News' request for comment.
ABC News’ Candace Smith contributed to this report.