UPDATED with video: There was a good, old-fashioned screaming match outside the Oval Office between White House Chief of Staff John Kelly and National Security Adviser John Bolton, Stephen Colbert reported on Late Show.

They were fighting about the recent surge in border crossings. Bolton blames Secretary Kirstjen Nielsen and said she needed to start doing her job. Kelly, who previously held the job and recommended Nielsen to replace him, took issue with the crack.

Profanity was exchanged outside the Oval Office.

Good thing they did not do that inside the Oval Office, said a relieved Colbert. That office is intended for “the sacred presidential duty of tweeting about porn stars being ‘horsefaces’.”

The fight between Bolton and Kelly had been brewing for a couple weeks.

“Fellas, don’t fight!” Colbert urged, assuring them, “You’re both terrible!”

Trump, who had tweeted knicker-knottedly in the morning about the surge, threatening to shut down the southern border, sided with Bolton. This added to Kelly’s fury. After the blow-up, aides whispered privately that one of the men might leave the White House, according to reports.