GOP presidential front-runner Donald TrumpDonald John TrumpConway defends herself against Hatch Act allegations amid threat of subpoena How to defuse Gulf tensions and avoid war with Iran Trump says 'stubborn child' Fed 'blew it' by not cutting rates 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 Cruz Hickenlooper, Bennet bring deep ties to 2020 debate stage 2020 Democrat Bennet releases comprehensive government reform plan GOP frets about Trump's poll numbers 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 RubioThe Memo: All eyes on faltering Biden ahead of first debate GOP lawmaker on Iran: Congress should vote on 'what's worthy of spilling American blood and what isn't' The Memo: Can Trump run as an outsider? 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."