Miami — 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 about it later.The White House didn't immediately comment.Trump has been criticised for not reaching out right away to relatives of the four US soldiers 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.