After South Carolina Sen. Lindsey Graham called GOP frontrunner Donald Trump a “jackass,” Trump read out Graham’s private cell phone number during a Tuesday press conference.

“I don’t care if he drops out. Stay in the race, just stop being a jackass,” Graham told CBS This Morning. “The world is falling apart. We’re becoming Greece. The Ayatollah’s on the verge of having a nuclear weapon, and you’re slandering everybody and anybody to stay in the news. You know, run for president, but don’t be the world’s biggest jackass.”

Trump, apparently, wasn’t having it.