Trump's success with voters, despite sometimes saying things only to contradict them later, has also alarmed many leading figures within his own party. Some of them are openly plotting to try to prevent him from becoming the nominee at the party's national convention in July.
Reince Priebus, the Republican National Committee chairman, said on Sunday that voters were "afraid" of their economic situation when asked about Trump's remarks on CNN's "State of the Union" show.
"When people are afraid and when they're angry, sometimes people say things that they regret," he said, apparently referring to Trump's remarks. "The truth is that people are concerned about the future, and every candidate is going to communicate their message differently."
He also played down speculation that party leaders will seek to dislodge Trump by helping someone who is not yet even a declared candidate prevail at the convention, which becomes governed by complicated voting rules if no candidate arrives with a clear majority of votes.
"I think that our candidate is someone who's running," Priebus said, referring to Trump, U.S. Senator Ted Cruz of Texas and Ohio Governor John Kasich. The candidates will next face voters on Tuesday in Wisconsin, where recent polls tend to show Cruz holding a small lead over Trump.