President Donald Trump told the widow of a slain soldier that he "knew what he signed up for," according to a Florida congresswoman.

Rep. Frederica Wilson said she was in the car with Myeshia Johnson on the way to Miami International Airport to meet the body of Johnson's husband, Sgt. La David Johnson, when Trump called. Wilson says she heard part of the conversation on speakerphone.

When asked by Miami station WPLG if she indeed heard Trump say that she answered: "Yeah, he said that. To me, that is something that you can say in a conversation, but you shouldn't say that to a grieving widow." She added: "That's so insensitive."

Sgt. Johnson was among four servicemen killed in an ambush in Niger earlier this month.

Wilson, a Democrat, said she did not hear the entire conversation and Myeshia Johnson told her she couldn't remember everything that was said when asked it about it later.

The White House didn't immediately comment.

Trump has been criticized for not reaching out right away to relatives of the four killed in Niger. On Monday, Trump said he'd written letters that had not yet been mailed. His aides said they had been awaiting information before proceeding.