Washington(CNN) White House chief of staff John Kelly, in an extraordinary and at times emotional statement Thursday, said he was "stunned" by what a Democratic congresswoman told reporters after she listened in on President Donald Trump's call to the widow of a fallen soldier.

Kelly, a Gold Star father, said he was "brokenhearted" by the congresswoman's criticism and said that he had advised Trump on what to say before he called the families of the four fallen soldiers who died during an ambush in Niger. Kelly said he encouraged Trump to echo words Gen. Joseph Dunford offered to Kelly when his own son was killed in Afghanistan.

"He was doing exactly what he wanted to do when he was killed. He knew what he was getting into by joining that 1%. He knew what the possibilities were because we were at war," Kelly said, channeling Dunford's words to him upon the death of Kelly's son. "And when he died he was surrounded by the best men on this earth, his friends. That's what the President tried to say to the four families the other day."

Rep. Frederica Wilson told CNN Tuesday evening that Trump told the widow that her husband "knew what he signed up for, but I guess it still hurt."

Wilson, who listened in on the call via speakerphone because she is close with the family, said on CNN's "New Day" Wednesday morning that Trump didn't appear to know Sgt. La David Johnson's name and that his widow "broke down" after her call with the President. Johnson was among the four US soldiers killed by enemy fire in the October 4 ambush.

Cowanda Jones-Johnson, a family member who raised Johnson, told CNN Wednesday that Wilson's account of the call between Trump and Johnson's widow, Myeshia, was "very accurate."

Trump denied Wilson's account in both a tweet and a statement made at the White House.

While Kelly did not contradict Wilson's account, he suggested her decision to speak out about the conversation "eroded a great deal" the sacrifice of men and women in uniform.

"Let's not let this maybe last thing that is held sacred in our society, a young man, a young woman going out and giving his or her life for our country, let's try to somehow keep that sacred," Kelly said.

Extraordinary appearance

Kelly prefaced his criticism by drawing on his own experiences losing a son -- which he rarely discusses publicly -- to paint a picture for Americans of the ultimate sacrifice only a sliver of the population will ever know.

In gut-wrenching detail, Kelly spoke of the meticulous process by which the bodies of American troops are returned to the United States -- "their first stop is when they are packed in ice" -- and spoke of military casualty officers proceeding "to break the heart of a family member" by informing them of their child or spouse's death.

He spoke of war buddies phoning families, like his, to share stories of the fallen and said the letters from commanders and the President of the United States don't help ease the pain.

Kelly's place at the podium came days after Trump pulled his chief of staff into the political storm by saying in an interview with Fox News: "You could ask General Kelly, did he get a call from Obama?"

The answer to that question was no, Kelly said Thursday, though he stressed "that was not a criticism."

In fact, Kelly said he advised Trump not to phone the families of fallen soldiers because "if you're not in the family, if you've never worn the uniform, if you're not in combat, you can't even begin to imagine how to make that call."

When Trump insisted on making the calls, Kelly offered advice.

But Kelly said Wilson exhibited "selfish behavior" with her account of the call.

The former four-star Marine Corps general said Wilson's words prompted him to leave the White House to go to Arlington National Cemetery and "go walk among the finest men and women on this earth."

Politicizing a soldier's death

But while Kelly expressed his anger at the politicization of the death of American soldiers, he also chose to ignore Trump's role in stoking it in the first place.

Kelly did not remark on Trump's decision to publicly invoke the death of Kelly's son, though sources told CNN on Wednesday that Kelly did not know Trump would make that conversation public.

He also papered over Trump's decision to compare his communications with the families of fallen soldiers with those of his predecessors, namely Presidents Barack Obama and George W. Bush.

Kelly did say that he believed phone calls and even letters from US presidents could not "lighten the burden on these families" and said he advised Trump against the phone calls.

Kelly said he advised the President to not make the phone calls because there is "no perfect way" to call the family of a fallen soldier.

"He said to me, 'What do I say?' I said to him, 'Sir, there is nothing you can do to lighten the burden on these families.'"

Kelly's decision to step into the spotlight Thursday in an attempt to change the conversation dogging the White House also marked one of the only instances Kelly has publicly invoked the death of his son, 1st Lt. Robert Kelly, who was killed in Afghanistan in 2010.

Kelly has largely grieved privately and when he has spoken about military sacrifice, he has spoken broadly about shared experiences.

Kelly was also peppered Thursday with questions about the death of the four American soldiers who were killed in an ambush in Niger, which the military is investigating. He declined to offer new details about how the soldiers were ambushed and how Johnson's body was recovered nearly 48 hours after the ambush.