Donald Trump said Republican leaders better get used to him being in the race.

Donald Trump speaks to the crowd at a town hall meeting in Aiken, South Carolina. (Photo by Sean Rayford/Getty Images)

He then gave another warning that he may run as a third-party candidate if he does not get the nomination.

Trump said he has been hearing rumors of a brokered convention where party officials, not voters actually choose the nominee.

He said if true it would violate an agreement he signed saying he would not run as a third-party candidate.

While Trump is leading nationally, he is now trailing in Iowa.