A FAMILY in the United States is at the centre of a dispute with Donald Trump that has the nation — and the world — talking.

So outrageous are Trump’s comments over the Khan family, US Senator John McCain has come out swinging against the Republican presidential candidate, blasting him for his attack on the parents of the Muslim US Army officer killed in the Iraq war.

In a scathing and lengthy statement issued Monday, the Arizona Republican waded into the dispute between his party’s controversial nominee and Khizr and Ghazala Khan, whose son, Army Captain Humayun Khan, was killed by a bomb in Iraq in 2004.

“While our Party has bestowed upon him the nomination, it is not accompanied by unfettered licence to defame those who are the best among us,” wrote McCain, who was a prisoner of war for more than five years during the Vietnam War.

Trump’s emotionally-charged feud with the Khans has been the talk of the election campaign in recent days after Khizr Khan spoke at the Democratic National Convention on Thursday night, with his wife standing at his side.

“In recent days, Donald Trump disparaged a fallen soldier’s parents. He has suggested that the likes of their son should not be allowed in the United States — to say nothing of entering its service,” McCain said. “I cannot emphasise enough how deeply I disagree with Mr Trump’s statement. I hope Americans understand that the remarks do not represent the views of our Republican Party, its officers, or candidates.

“In the end, I am morally bound to speak only to the things that command my allegiance, and to which I have dedicated my life’s work: the Republican party, and more importantly, the United States of America. I will not refrain from doing my utmost by those lights simply because it may benefit others with whom I disagree,” the statement continued.

On the final night of week’s DNC in Philadelphia, Mr Khan spoke emotionally of the sacrifice his son had made for the country as an American Muslim, taking aim at Trump’s proposal to ban Muslims from entering the US.

“Let me ask you, have you even read the United States constitution? I will gladly lend you my copy,” Mr Khan said, amid cheers. “You have sacrificed nothing.”

In response to the powerful speech, Trump stoked outrage by implying that Mr Khan’s wife was blocked from speaking while standing alongside her husband because of her religion.

He also questioned whether Mr Khan’s words were his own. “Who wrote that? Did Hillary’s scriptwriters write it?” Trump said an interview with NBC’s George Stephanopoulos on Sunday.

Trump also pointed out that he had made sacrifices in his life, by employing “thousands and thousands of people”. The reaction quickly caused Twitter to light up with the hashtag #Trumpsacrifice, with users naming other things the billionaire businessman may have given up.

"I had to pay people who worked for me" #TrumpSacrifice — aasif mandvi (@aasif) August 1, 2016

#trumpsacrifice once had to pay taxes...wait he doesn't, so just disregard this post. — Michael R. Hamel⛳ (@MHGURU) August 1, 2016

@stuartpstevens they once ran out of lobster at the Waldorf, and he had to have the Kobe steak. #trumpsacrifice — Joel Taylor (@jptaylorsg) July 30, 2016

Once had to fly commercial. #trumpsacrifice — RichardChinnis (@rchinnis) July 30, 2016

In his statement, McCain — whose service and capture in Vietnam was mocked by Trump last year — thanked the Khan family for immigrating to America, saying “your son was the best of America, and the memory of his sacrifice will make us a better nation — and he will never be forgotten”.

McCain also recalled how Humayun Khan died, saying that when a suicide bomber aimed his vehicle toward a building housing hundreds of US soldiers, the captain told his subordinates to stay away, then ran toward it.

In remarks to television networks on Monday, Mr Khan said the real estate mogul has a “black soul,” lacks empathy and is “totally unfit for the leadership of this country.”

Ghazala Khan also penned an open letter to Trump, published in the Washington Post on Sunday, revealing that she was too heartbroken to speak about her beloved son, Humayun Khan, in public last week.

Trump responded simultaneously on Twitter to the parents’ morning TV appearances, saying he was being “viciously attacked” and then attempting to shift the focus away from the Khan family.

Mr. Khan, who does not know me, viciously attacked me from the stage of the DNC and is now all over T.V. doing the same - Nice! — Donald J. Trump (@realDonaldTrump) August 1, 2016

This story is not about Mr. Khan, who is all over the place doing interviews, but rather RADICAL ISLAMIC TERRORISM and the U.S. Get smart! — Donald J. Trump (@realDonaldTrump) August 1, 2016

McCain’s forceful condemnation is the toughest rebuke to date on the issue from a senior Republican, while several others have weighed in to express support for the Khans.

McCain, nevertheless, has not pulled his endorsement but did appear to issue a warning to Trump in the statement: “It is time for Donald Trump to set the example for our country and the future of the Republican Party,” he wrote.

The Veterans of Foreign Wars (VFW), as well as a group of Gold Star families of fallen service members also demanded Trump apologise for his comments about the parents of the slain Muslim US soldier.

“Your recent comments regarding the Khan family were repugnant and personally offensive to us,” wrote a group of 11 Gold Star families in a letter published Monday on VoteVets.org.

“We feel we must speak out and demand you apologise to the Khans, to all Gold Star families, and to all Americans for your offensive, and frankly anti-American comments.”

The letter continued: “Ours is a sacrifice you will never know. Ours is a sacrifice we would never want you to know.”

In an interview in July 2015, Trump questioned whether McCain, a former Navy pilot who spent more than five years as a North Vietnamese prisoner, was indeed a war hero. “He was a war hero because he was captured. I like people who weren’t captured,” he said at a conference in Iowa.