The war of words between Republican presidential candidates Donald Trump and Lindsey Graham kicked up yet another notch Tuesday as Trump punctuated a round of name-calling by publicly reading out Graham's phone number to supporters at a South Carolina rally. 

The two have been trading jabs anew ever since Trump questioned the "war hero" status of Sen. John McCain, R-Ariz., a friend of Graham's, over the weekend. 

Earlier on CBS’s “This Morning,” Sen. Graham, R-S.C., called Trump a “jackass.” He said Trump is “slandering everybody and anybody to stay in the news. You know, run for president, but don't be the world's biggest jackass.”

Trump fired back, claiming Graham asked the businessman several years ago to give him a “good reference” for a Fox News show. 

“So Lindsey Graham says ‘please, please whatever you can do’ and so I’m saying to myself, what is this guy a beggar … He said could you mention my name, I said yes.”

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Trump then showed the audience a card, on which he wrote down Graham’s apparent phone number, and shared it with them. “I don’t know if it’s the right number, let’s try it … so I don’t know, it's three, four years ago so maybe it’s an old number … give it a shot.”

After sharing the number, Trump kept up his attacks on Graham, pointing to recent poll numbers.

“I see your senator – what a stiff, Lindsey Graham, by the way, he’s registered zero in the polls, and he’s on television all the time.”

The latest Fox News poll has Trump in first with 18 percent and Graham polling at less than 1 percent. Trump has faced criticism from virtually every other presidential candidate for saying Saturday that McCain was a war hero just because he got "captured." 

This isn’t the first time Trump has sent out a number to the masses.

In June, he posted on Instagram a hand-written letter apparently sent from Univision anchor Jorge Ramos asking Trump for an interview. That came after the broadcaster’s decision to cut ties with Trump over his controversial remarks on illegal immigration.

Fox News' Christopher Snyder contributed to this report.