CHICAGO (CBS) — Controversial ads have appeared on 10 CTA buses–and the transit agency says it could do nothing to prevent them from running.

The ad boards, purchased by the New York-based American Freedom Defense Initiative (AFDI), sport a variety of messages.

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One such billboard reads, “In any war between the civilized man and the savage, support the civilized man.” It then concludes, “Support Israel. Defeat jihad.”

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CTA spokesman Brian Steele said Wednesday that no legal action was threatened by AFDI. However, a letter to CTA ad agent Titan360, posted on AFDI Executive Director Pamela Geller’s blog and dated Oct. 23, did exactly that.

“If I do not receive a definitive and affirmative response to my clients’ ad buy by the close of business (Oct. 23), this firm will initiate federal litigation and we will, as we have in the past, seek temporary and preliminary injunctive relief, and upon the successful conclusion of the litigation, we will seek, and we will recover, as we have in the past, attorney’s fees and costs. The choice is yours,” wrote AFDI attorney David Yershalmi.

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Steele said in a statement that Geller’s group has prevailed in court against transit agencies in New York and Washington, D.C., and said CTA has no choice but to run the ads, even though it objects to the messages, which he called “divisive.”

AFDI spent $4,500 for the ads, which will run for four weeks; the 10 buses are scattered among three CTA garages.

The ads drew immediate criticism from the Jewish Council on Urban Affairs, which has tried to build bridges with the Muslim community. Its programs director, Asaf Bar-Tura, called the ads “demeaning and hateful” and Geller an extremist.

“We will not stand silently when a smear campaign against our Muslim friends and neighbors appears on our city’s buses,” Bar-Tura said in a statement.

Geller responded in her blog by calling Bar-Tura “weak, feckless and a dangerous tool.”

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Geller has staked out a number of controversial positions. She is among those who maintains that President Obama’s birth certificate was forged.