Donald Trump was criticized for his silence after the death of four U.S. members of the armed forces in Niger. When the president finally acknowledged one of the slain men, it was appalling what he reportedly said to the widow, according to a congresswoman.

Rep. Frederica Wilson (D-Fla) claims she was present when the condolence call was made to Myeshia Johnson, the widow of Sgt. La David Johnson. Trump reportedly told the widow that her husband "knew what he signed up for ... but when it happens it hurts anyway."

"Yeah, he said that," Wilson said Tuesday. "So insensitive. He should not have said that. He shouldn't have said it."

The president called about 4:45 p.m. and spoke to Johnson's pregnant widow for about five minutes. She is the mother of Johnson's surviving 6-year-old daughter and 2-year-old son. Wilson later added on CNN's "New Day" that Trump didn't know the name of the service member and that his widow "broke down" after her call with the president.

Trump fired back Wednesday morning in a tweet, claiming the congresswoman "fabricated" what he said and that he has proof. Wilson shot back at Trump just moments later.

"I don't know what kind of proof he could be talking about," Wilson said Wednesday on CNN. "I'm not the only person that was in the car. And I have proof too. This man is a sick man. He's cold-hearted, and he feels no pity or sympathy for anyone."

Cowanda Jones-Johnson, a family member who raised Johnson, backed up Wilson's claim, saying she was in the car as well when the call happened. She told CNN Wednesday that Wilson's account of the call between Trump and Johnson's widow, Myeshia, was "very accurate."

In addition to taking days to discuss the attacks publicly, Trump also falsely claimed that former President Barack Obama didn't call families of fallen service members.