Washington (CNN)Donald Trump said Thursday that while Texas Sen. Ted Cruz and retired neurosurgeon Ben Carson are surging behind him in the polls, he doesn't want to attack them because they've been nice to him.
Donald Trump: No attacks on Ben Carson, Ted Cruz -- yet
"I cannot hit him. He's been so nice to me," Trump said Thursday at an event in South Carolina of Carson, adding that Cruz fell in the same category.
But speaking of Cruz, Trump warned: "I may have to if he starts getting really close. I may have to."
Trump's remarks come as Carson and Cruz are rising in recent polls, with Carson landing in second place behind Trump in the latest Quinnipiac University poll released Thursday. Cruz tied at 7% with the Floridians, Sen. Marco Rubio and former Florida Gov. Jeb Bush. Trump led with 28%.
Trump said that he "used to think (Bush) was the guy to beat," but said that might no longer be the case.
Trump spoke Thursday at the Upstate Chamber Coalition in Greenville, South Carolina, drawing a record-breaking 1,400 attendees to the group's "presidential series," which as already hosted six other GOP presidential contenders, according to Katie Busbee, one of the event's organizers.
Trump ran through his classic, off-the-cuff style stump speech Thursday, insisting he would be the best president -- and the most capable Republican to win the White House as the nominee.
The GOP front-runner addressed criticism of his tone, saying he views it as "energy."
"We need tone. We need tough tone," Trump told the attendees, pointing to ISIS's beheadings of Christians. "They're talking about my tone ... We need tough tone. We're going to be -- we're not going to have a country."
And Trump also insisted he is not a hothead, saying that he has the "perfect temperament" to be president.
He even pointed to a recent doctor's examination, saying that his blood pressure was logged at 110, a healthy level.
"Nobody believes I have low blood pressure!" Trump exclaimed.