Mr Trump was among 10 Republican presidential hopefuls seeking to woo several thousand socially conservative evangelical voters at the annual Family Leadership Summit in Ames, Iowa.

At the Family Leadership Summit in Ames, Iowa, Trump said (via Politico): “He’s not a war hero”.

After weeks in which his fellow Republican presidential candidates tried to ignore, hedged about, and, in some cases, even embraced Donald Trump, the outspoken real estate mogul with the skyrocketing poll ratings may finally have given his rivals an opening.

Sen. Ted Cruz (R-Tex.), who has been perhaps the loudest defender of Trump’s remarks about immigrants and met privately with Trump a few days ago in New York, refused to condemn Trump over his comments about McCain.

Donald Trump should apologize immediately for attacking Senator McCain and all veterans who have protected and served our country”, Perry also said in the statement.

When I repeated the question, Trump said: “I am not blaming John McCain for his capture”. Trump used the opportunity to launch an attack on John McCain, who Trump sees as an unworthy war hero. McCain spent more than five years in a Vietnamese prisoner of war camp after his plane was shot down.

While Trump did not apologize for his comments after the event, he sought to limit his message to McCain. According to The Smoking Gun, which obtained selective service records for Trump in 2011, he received four student deferments between 1964 and 1968, and later a medical deferment in 1968.

Former Texas Gov. Rick Perry said the comment makes Trump “unfit to be commander-in-chief”.

Trump has recently spoken out more forcefully against McCain, after the veteran senator denounced Trump for “firing up the crazies” during a speech last week in Phoenix. He says questioning a person’s military valor in the political arena is a low blow. “Bigger than Bernie Sanders”, Trump said. Former Florida governor Jeb Bush condemned “slanderous attacks” against McCain, in a tweet. The former host of Celebrity Apprentice also took a populist note in going after the current system of campaign finance. Instead, Cruz on Saturday blamed the media for trying to pit Republicans against each other.

“Let me tell you who is an American hero – the family that stays behind”, he said.

In response, Trump demanded an apology, and tweeted that McCain is a “dummy.”

Rubio’s position, like most of his party’s 2016 contenders, moves further away from Republican leaders’ previous calls to embrace comprehensive immigration reform heading into a presidential election where Hispanic voters are expected to play a critical role.

“To disparage a legitimate American hero like John McCain – you may disagree with his politics, and that’s fine”, he continued.

“He’s not a war hero”, Trump said. “I have nothing but respect for his service to our country”.

Compared to Perry, U.S. Sen.

At a testy press conference after his performance, and as the real-time scorn for his comments dominated Twitter, Trump doubled-down.