GOP presidential front-runner Donald TrumpDonald John TrumpZuckerberg launches public defense of Facebook as attacks mount Trump leaning toward keeping a couple hundred troops in eastern Syria: report Warren says making Israel aid conditional on settlement building is 'on the table' MORE promised late Thursday night that he would no longer curse on the campaign trail.

“I won’t use foul language,” he told supporters during a rally in Baton Rouge, La.

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“I’m just not going to do it. I’ll never do it again, actually, and I’ll never even copy what somebody asks me to say.”

Trump’s rivals for the Republican presidential nomination have criticized his public profanity as crass and undignified.

“I’m not sure a lot of voters are excited about having a president who, when he gets rattled or gets upset, he begins cursing and yelling vulgarities,” rival candidate Ted CruzRafael (Ted) Edward CruzHillicon Valley: GOP lawmakers offer election security measure | FTC Dem worries government is 'captured' by Big Tech | Lawmakers condemn Apple over Hong Kong censorship Lawmakers condemn Apple, Activision Blizzard over censorship of Hong Kong protesters The Hill's Morning Report — Trump's impeachment jeopardy deepens MORE said in Fort Mill, S.C., late Thursday evening, according to MSNBC.

“You turn on the TV and you see a leading presidential candidate saying profanity from a stage,” Marco RubioMarco Antonio RubioTurkey says soldier killed despite cease-fire in Syria White House staggers after tumultuous 48 hours Erdoğan got the best of Trump, experts warn MORE, another GOP contender, said the same day in Okatie, S.C. "Profanity from a stage. All these things undermine what we teach our children.”

Trump has repeatedly vowed he will “bomb the shit” out of the Islamic State in Iraq and Syria as president. He recently sparked outrage for echoing a supporter who called Cruz a “pussy."