Donald Trump continued his political attacks on everyone at a campaign event in South Carolina on Tuesday, slamming fellow Republicans and Democrats alike.

But he took things a step further when he gave out the phone number of sitting U.S. senator and fellow Republican hopeful Lindsey Graham.

See also: The Donald Trump campaign speech that never saw the light of day

Trump claims that the South Carolina senator called him last year looking for campaign donations.

Speaking at a rally in Sun City, Trump questioned Graham's intelligence, saying, "He doesn’t seem like a very bright guy." He then called out a telephone number, that began with Washington, D.C's area code 202, and produced a piece of paper with the number written on it from his pocket.

Mashable called the number and found it directed to a voicemail. A woman's voice said: "Lindsey Graham."

Later, callers were told the mailbox was full.

Both Time and CBS News confirmed that the number was indeed Graham's cell phone.

The disclosure came after Graham called Trump a "jackass" on national television Tuesday morning, when discussing controversial comments the real estate magnate made about John McCain's role in the Vietnam War.

"I don't care if he drops out. Stay in the race, just stop being a jackass," Graham on CBS This Morning.

Later in the day, Graham responded to Trump's leak, tweeting, "Probably getting a new phone. iPhone or Android?"

Probably getting a new phone. iPhone or Android? — Lindsey Graham (@LindseyGrahamSC) July 21, 2015

His campaign manager also issued a statement that said in part, “Donald Trump continues to show hourly that he is ill-prepared to be commander in chief."