Republican presidential nominee Donald Trump speaks at a campaign rally in Colorado Springs, Colorado, U.S., July 29, 2016. REUTERS/Carlo Allegri

UPDATE, July 31, 4:30 p.m.EDT -- Donald Trump's war of words with the parents of a U.S. soldier killed in Iraq heated up Sunday when Ghazala Khan, the mother of Humayun Khan, published an op-ed in the Washington Post.

Trump has offended many individuals and groups during his campaign, including war hero Sen. John McCain, a former P.O.W. But on Sunday it appeared that his criticism of the family of Captain Khan might hurt him politically, as both Democrats and Republicans rejected his comments.

Trump had speculated that Ghazala Khan did not speak at the convention because strict Muslim rules kept her silent.

"Donald Trump has asked why I did not speak at the Democratic convention," she wrote. "He said he would like to hear from me.

Here is my answer to Donald Trump: Because without saying a thing, all the world, all America, felt my pain. I am a Gold Star mother. Whoever saw me felt me in their heart."

"Every day I feel the pain of his loss. It has been 12 years, but you know hearts of pain can never heal as long as we live. Just talking about it is hard for me all the time. Every day, whenever I pray, I have to pray for him, and I cry. The place that emptied will always be empty.

I cannot walk into a room with pictures of Humayun. For all these years, I haven’t been able to clean the closet where his things are — I had to ask my daughter-in-law to do it. Walking onto the convention stage, with a huge picture of my son behind me, I could hardly control myself. What mother could? Donald Trump has children whom he loves. Does he really need to wonder why I did not speak?"

Her essay concluded by criticizing the Republican nominee's understanding of Islam.

"When Donald Trump is talking about Islam, he is ignorant. If he studied the real Islam and Koran, all the ideas he gets from terrorists would change, because terrorism is a different religion.

Donald Trump said he has made a lot of sacrifices. He doesn’t know what the word sacrifice means."

Her husband, Khizr Khan, said Trump was temperamentally and morally unfit to be president. He called on Senate Majority Leader Mitch Mcconnell and House Speaker Paul Ryan, Republican party leaders, to repudiate him.

"Two things are absolutely necessary in any leader or any person that aspires, wishes to be a leader. That is moral compass and, second, is empathy. This candidate is void of both traits that are necessary for the stewardship of this country," Khan told CNN.

"He is a black soul. And this is totally unfit for the leadership of this beautiful country."

Original story: Responding to comments made by the father of a Muslim U.S. soldier killed in Iraq, Donald Trump cited his own “sacrifices” during an interview with ABC News’ George Stephanopoulos. In his remarks, the Republican presidential nominee — who has called for a temporary ban on Muslims entering the U.S. — also implied that the mother of the soldier remained silent during the speech because “she wasn't allowed to have anything to say.”

“I think I've made a lot of sacrifices. I work very, very hard. I've created thousands and thousands of jobs, tens of thousands of jobs, built great structures. I've done, I've had tremendous success. I think I've done a lot,” Trump said. “I think when I can employ thousands and thousands of people, take care of their education, take care of so many things, even in military. I mean, I was very responsible, along with a group of people, for getting the Vietnam Memorial built in downtown Manhattan, which to this day people thank me for.”

“Oh, sure. I think they're sacrifices,” Trump responded when probed further.

In a statement released late Saturday, Trump called Humayun Khan — the slain U.S. Army captain — a “hero.” However, he added that Humayun’s father Khizr Khan “has no right to stand in front of millions of people and claim I have never read the Constitution and say many other inaccurate things.”

Khizr Khan had stated, during a speech at the Democratic National Convention on Thursday, that Trump had “sacrificed nothing and no one.”

“Donald Trump consistently smears the character of Muslims. He disrespects other minorities, women, judges, even his own party leadership. He vows to build walls and ban us from this country . ... Let me ask you: Have you even read the U.S. Constitution? I will gladly lend you my copy. In this document, look for the words liberty and equal protection of law ,” Khan said in his impassioned speech. “Have you ever been to Arlington Cemetery? Go look at the graves of the brave patriots who died defending America — you will see all faiths, genders and ethnicities.”

Khizr’s wife Ghazala rebuffed Trump’s suggestion that she did not speak at the convention because it was forbidden by her religion.

“I don't know what type of Islam he has read or heard. I'm so sorry about that, that he has not had any idea what the Islam is,” she told ABC News. “I am very upset when I heard when he said that I didn't say anything. I was in pain. If you were in pain you fight or you don't say anything, I’m not a fighter, I can't fight. So the best thing I do was quiet.”

Democratic vice presidential nominee Tim Kaine also expressed shock at Trump’s comments on the Khans, stating that his remarks demonstrated his “temperamental unfitness.”

“He was kind of trying to turn that into some kind of ridicule,” Kaine reportedly said after a campaign event in Pittsburgh. “If you don't have any more sense of empathy than that, then I'm not sure you can learn it.”