(CNN) Speaking in front of hundreds at a rally in South Carolina on Tuesday, Donald Trump read a number he said people could use to reach South Carolina Sen. Lindsey Graham's private cell phone.

Trump and Graham have engaged in an ongoing feud in the past few days as they battle for the Republican presidential nomination. In Trump's speech Tuesday, he called Graham an "idiot," after Graham called him a "jackass," in an interview Monday with CNN's Kate Bolduan.

Trump gave out the number and urged attendees to call it.

"Give it a shot," Trump said, urging people to call the state's senior senator.

When CNN called the number, it went directly to voicemail and the recorded message said it was the phone number for Graham. The mailbox was full.

A text message to Graham using the number was not returned.

Immediately following Trump's rally, Graham's campaign manager released a statement saying that the only people excited about Trump's presidential bid are President Barack Obama and 2016 Democratic front-runner Hillary Clinton.

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

Graham also joked shortly thereafter that he might need a new phone now.