WASHINGTON -- Donald Trump wouldn't apologize Sunday after igniting a political firestorm a day earlier by questioning whether Sen. John McCain -- who spent five years as a prisoner during the Vietnam War -- is a war hero.
Asked by ABC News whether he owes McCain an apology, Trump said: "No, not at all."
"People that fought hard and weren't captured and went through a lot, they get no credit. Nobody even talks about them. They're like forgotten. And I think that's a shame, if you want to know the truth," Trump said Sunday.
"People that were not captured that went in and fought, nobody talks about them. Those are heroes also," he said.
In an interview on Fox News, Trump hit the Arizona senator again, saying McCain has failed to play a positive role in fixing veterans' lagging health care system.
"He's all talk and he's no action," Trump said.
He also compared the criticism he's faced from Republican presidential contenders to the blowback his comments on undocumented immigrants from Mexico.
"I brought illegal immigration to the forefront. I believe now I'm bringing the veterans -- the plight of the veterans -- to the forefront," Trump said.
Trump's comments came Saturday in Iowa. By mid-afternoon, Trump tried to walk back his blunder on Twitter, saying "captured or not, all our soldiers are heroes!"
But his attempt at damage control seemed unlikely to diminish the anger his remarks had caused. They provoked an immediate outcry from his 2016 presidential rivals and the Republican National Committee, which has expressed concern about the impact his controversial remarks on immigration have had on the GOP brand.
For Republicans waiting to pounce on Trump and knock him from his position as the party's leading presidential candidate, the real estate mogul may have handed them an opening.
The controversy began when Trump, speaking at a question-and-answer session at the Family Leadership Summit in Ames, Iowa, commented on McCain, with whom he's recently feuded over illegal immigration.
"He is not a war hero," Trump told pollster Frank Luntz, who was hosting the session.
"He is a war hero," Luntz interjected.
"He is a war hero because he was captured," Trump said, cutting him off. "I like people that weren't captured, OK? I hate to tell you. He is a war hero because he was captured. OK, you can have -- I believe perhaps he is a war hero."
The comments met with a mix of gasps, boos, laughter and some applause from an audience.
McCain, a Naval aviator, was shot down in 1967 over North Vietnam and fractured both arms and legs after being ejected from his aircraft. He was repeatedly tortured during his stay in the notorious "Hanoi Hilton" -- and refused early release when the North Vietnamese learned his father was a Navy admiral -- until he finally returned home in 1973 following the Paris Peace Accords.
The Arizona senator, who has limited mobility in his arms following his war experience, received the Distinguished Flying Cross, a Silver Star and a Purple Heart for his service.
Trump, meanwhile, received several deferments during the war. 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.
McCain spokesman Brian Rogers told CNN that the senator would have no comment on Trump's statements.
But McCain's daughter, Meghan, tweeted that she was "horrified" and "disgusted" by the remarks.
"I can't believe what I am reading this morning," she said. "There are no words."