An atheist group is suing a Pennsylvania transit system over its refusal to run ads with the word “atheists” on the sides of buses.

The County of Lackawanna Transit System repeatedly rejected the ads sought by the Northeastern Pennsylvania Freethought Society, telling the group it doesn’t permit advertising space to be used as a forum for public debate. The transit system also told the group its ad might offend riders and hurt revenue.

The atheist group filed suit Tuesday in federal court in Scranton. The suit says COLTS allowed many religious groups to advertise before the Freethought Society tried placing its ad in 2012.

The group wants a judge to force COLTS to run the “atheists” ad.

The transit system’s lawyer is reviewing the suit. He’s expected to comment later.

In New York, The nation’s largest mass transit system was preparing to ban all political advertising on its subways and buses after a judge ruled that a pro-Israel group was allowed to display an advertisement containing the phrase “Hamas Killing Jews” on New York City buses.

The resolution was expected to pass Wednesday at the Metropolitan Transportation Authority’s board meeting.

The cash-strapped agency says such advertising only accounts for less than $1 million of its annual advertising revenue of $138 million. Officials say New York is following in the footsteps of cities including Chicago and Los Angeles, which have already banned political ads on public transit.

The judge said in a decision made public last week that the advertisement is protected speech. The MTA has argued that the ad could incite violence.