"Donald Trump falls to second place behind Ben Carson," Trump said, reading the headline of the day. "We informed Ben, but he was sleeping."  He added that Carson could not aggressively tackle trade in the way Trump has pledged to do and said the country needs a "special leader" with "tremendous energy" as president. And in more subtle ways, Trump hinted at a contrast between him and Carson as he pointed out that the U.S. needs a strong leader in the face of "medieval times" in which ISIS is beheading Christians.  The attacks mark an end to the détente Trump and Carson have mutually maintained, though Carson said earlier Friday that he would not respond to incoming fire from Trump. But Trump's unprompted assault could change the tone of their relationship, which was cordial if not friendly during the previous debate, and threatens to undermine Trump's claim that he only punches back when attacked.  Carson: I won't respond to Trump if he attacks  Trump also said he did not "believe" the results of the Quinnipiac University and Des Moines Register/Bloomberg Politics polls on Thursday and Friday that showed Carson seizing the lead in Iowa.  "I don't believe those polls by the way because both of those pollsters disagree with me," Trump said. "Both of those polling groups do not like me at all and I disagree (with the results)."  But Trump's line of attack on stage veered from what he told Tapper in the interview shortly before taking the stage.  Trump in that interview said he accepted the polls' results, but said he was "really surprised" and did not "understand" them.  "It means I have to work a little bit harder in Iowa," Trump said.  In the interview, Trump also slammed Carson for favoring amnesty. Carson supports giving undocumented immigrants guest worker status if they come forward and report their presence in the country, but has denied the characterization of his plan as amnesty.  But it was Trump's own stance on immigration and the controversial comments he has made about undocumented immigrants that stalked his rally on Friday.  Trump slams Carson amid dipping poll numbers in Iowa  Three groups of a handful of protesters disrupted Trump's speech at different moments. His supporters vigorously drowned out the protesters with boos, cheers and shouts of "USA," "We want Trump" and "Go home."  Mindful that past protests have pushed some of his supporters to physical violence, Trump urged the crowd "don't hurt 'em, don't hurt 'em" and pointed out that they were exercising their freedom of speech.  But still, some supporters jostled with the protesters, pushing and grabbing them as they were shuffled out of the room.  Trump's counter on this matter, as always, was in his words.  "I'm gonna win with Hispanics," he declared. "I love the Hispanics."  CNN's Noah Gray contributed to this report.
Donald Trump on Friday downplayed the results of two Iowa polls that show him slipping to second place in the key first state, and he took shots at Iowa's new front-runner: Ben Carson.