By Jose Serrano (staff@latinospost.com) | First Posted: Jul 21, 2015 07:27 PM EDT

The sophomoric war of words between Sen. Lindsey Graham and real estate mogul Donald Trump reached a childish low Tuesday as Trump released his presidential candidate opponent's phone number.

Holding a rally in Graham's home state of South Carolina, Trump brandished a piece of paper, saying "so he gave me his number, and I found the card. I wrote the number," before reading the digits twice aloud. The front-running Republican acknowledged it might not be in service anymore but said to "give it a shot."

Trump - who called Graham an "idiot" and a "lightweight" earlier in the speech - said he got the phone number years back when the senator begged him for a good reference on a Fox News program. A call to the given number led to a voicemail recording stating Graham's mailbox was full.

Last month, Trump pulled off a similar stunt by uploading Univision anchor Jorge Ramos's letter to Instagram. Ramos included his cell phone number in an interview request following derogatory comments Trump made about Mexicans.

For his part, Graham posted a facetious response to Twitter.

On Monday, Graham appeared on CNN's "Erin Burnett OutFront" where he called Trump a "jackass" for snide remarks made about Arizona Sen. John McCain.

"What he said about John, I think, was offensive. He's becoming a jackass at a time when we need to have a serious debate about the future of the party and the country," Graham told CNN's Kate Bolduan. "This is a line he's crossed, and this is the beginning of the end of Donald Trump...I am really pissed."

Fellow GOP presidential candidates shared Graham's sentiment. Former Florida Gov. Jeb Bush declared McCain is a "real hero" during a policy speech in Tallahassee, and former Texas Gov. Rick Perry said Trump's comments were a "bullet" to those wearing a military uniform.

"The reason they're hitting me is when you register zero in the polls, what the hell, you have nothing to lose," Trump, who insist he owes no apology, said during his speech Tuesday morning.

Christian Ferry, Graham's campaign manager, said in a statement that Trump continuously proves he is not ready for the presidency.

"The two people most excited about Donald Trump's candidacy are Barack Obama and Hillary Clinton," Ferry said.