A controversial advertisement with the slogan 'Killing Jews is worship' has been deemed fit for display on New York City buses. 

The ad was created by the American Freedom Defense Initiative (AFDI) and the full quote reads: "Killing Jews is worship that draws us close to Allah." 

A question underneath asks: "That's his Jihad.  What's yours?"

Alongside the text, a man glares menacingly, with a scarf concealing most of his face.

The Metropolitan Transport Authority (MTA) in New York wanted to refuse the "savage" ad on the grounds that it could incite terrorism and violence. 

Ruling on the case, U.S. District Judge John Koelti suggested the MTA's concerns about security were exaggerated, as the ad campaign has already run on public transport in Chicago and San Francisco without incident. 

He reasoned that the wording of the advert fell within the protections for free speech enshrined in the U.S. Constitution. 

"It strains credulity to believe that New Yorkers would be incited to violence by ads that did not incite residents of Chicago and San Francisco," he said.

He added: "Moreover, there is no evidence that seeing one of these advertisements on the back of a bus would be sufficient to trigger a violent reaction. Therefore, these ads—offensive as they may be—are still entitled to First Amendment protection."

The MTA has 30 days to appeal the ruling before it comes into effect.  A spokesman for the organisation said they were "disappointed" by the verdict and "reviewing our options".

The AFDI said the ad challenges Hamas and Islamic anti-Semitism.  It was celebrating the result, which it described as as "an important victory for the freedom of speech today".