By Dan Gilgoff and Dave Alsup, CNN

(CNN) - Delta Air Lines has pulled its advertising from “The Daily Show with Jon Stewart” over a skit in which Stewart featured a picture of a manger in between a naked woman’s legs, the company said Tuesday.

In the April skit, Stewart jokingly encouraged women to use “vagina mangers” to “protect their reproductive organs from unwanted medical intrusions.”

In a statement Tuesday, Delta Air Lines spokesperson Leslie Parker said that “We're always re-evaluating our advertising opportunities and updating our strategy in an effort to reach our desired audience.”

“Delta doesn't discriminate nor do we condone discrimination in regard to age, race, nationality, sexual orientation, religion or gender,” Parker’s statement continued. She said that Delta made the decision to pull its ads on Thursday.

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The Catholic League for Civil and Religious Rights, a conservative group that has waged a weeks-long campaign pressuring Stewart to apologize for the skit, had pressured Delta and other Comedy Central advertisers to pull their Daily Show ads.

Catholic League President Bill Donohue has encouraged a boycott of Kellogg’s because it has declined to pull its spots.

On Tuesday, Donohue announced that he’d sent a letter to the leadership at Viacom, the corporate parent of Comedy Central, which airs “The Daily Show.”

“You should be as offended as we are,” the letter said. “But if you are not, consider a picture of your own mother inserted there instead. Perhaps you now understand how the 80% of the nation that is Christian feel.”

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“What Stewart did wasn’t a joke,” Donohue’s letter continued. “It was hate speech. We could have pressed for him to be fired, but we did not. All we want is an apology.”

Media representatives at Comedy Central did not immediately respond to a request for comment. At a stand-up appearance in Florida last month, Stewart acknowledged the Catholic League’s campaign against him, according to the Tampa Bay Times.

“I'm not going to censor myself to comfort your ignorance," Stewart said, decrying what he called the cable news-fueled “outrage machine.”