Donald TrumpDonald John TrumpIvanka Trump pens op-ed on kindergartners learning tech Bharara, Yates tamp down expectations Mueller will bring criminal charges Overnight Cybersecurity: Equifax security employee left after breach | Lawmakers float bill to reform warrantless surveillance | Intel leaders keeping collusion probe open MORE struck back at Sen. Lindsey GrahamLindsey Olin GrahamDurbin: I had 'nothing to do' with Curbelo snub Republicans jockey for position on immigration Overnight Health Care: House passes 20-week abortion ban | GOP gives ground over ObamaCare fix | Price exit sets off speculation over replacement MORE on Tuesday, saying the South Carolina Republican had once asked him for a reference to be on Fox News and then giving out the senator's phone number to the crowd.

“It’s amazing, he doesn’t seem like a very bright guy. He actually seems to me not as bright, obviously, as [Texas Gov.] Rick Perry,” Trump said during a rambling speech Tuesday in Sun City, S.C.

“Didn’t this guy call me four years ago? Yes, he called me three or four years ago, Lindsey Graham, I didn’t even know who he was.”

After telling the crowd that Graham had called him "begging" for a good reference to be on Fox News's "Fox and Friends" and to see if he could come visit Trump to receive some campaign cash, Trump held up a sheet of paper with a telephone number on it that he said was Graham’s.

"He gave me his number and I found the card, I wrote the number down. I don't know if it's the right number, let's try it," he told the crowd.

"Your local politician, he won't fix anything but at least he'll talk to you.

A Graham aide confirmed to The Hill that the number was in fact the senator's cellphone.

Trump lambasted Graham a day after his fellow GOP presidential candidate called him "a jackass." 

Graham has ripped Trump over his criticism of Sen. John McCain (R-Ariz.), who Trump said was not a war hero despite the years he served as a prisoner of war in Vietnam.

Christian Ferry, Graham's campaign manager, criticized Trump as a side-show in a statement.

"Donald Trump continues to show hourly that he is ill-prepared to be commander in chief," he said.

"The two people most excited about Donald Trump's candidacy are Barack Obama and Hillary Clinton. Because of Trump's bombastic and ridiculous campaign, we aren't talking about Obama's horrible deal with Iran or Hillary Clinton's plans to continue Obama's failed national security agenda."

This story was updated at 1:30 p.m.