Donald Trump has lashed out at South Carolina senator Lindsey Graham, who made headlines for calling the Republican presidential candidate a “jackass”.
The billionaire businessman called Senator Graham a "lightweight" who couldn't get a job in the private sector.
He then read out the senator's phone number and urged the audience to call him.
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"This guy Lindsey Graham, he calls me a jackass," he said.
"I said to myself, ya know, it's amazing, he doesn't seem like a very bright guy.
"OK, he actually probably doesn't seems to me not as bright, honestly as Rick Perry. Rick Perry is probably smarter than Lindsey Graham, but what do I know?"
In the five weeks since Trump became a presidential candidate, he has insulted Mexican immigrants, rival White House contenders and Arizona Senator John McCain, his party's 2008 presidential nominee.
This does not seem to have bothered voters who have made Trump a surprise front-runner among the 16 candidates vying for the Republican Party nomination in the November 2016 election.
