"I think it is appalling what the congresswoman has done and the way she has politicized this issue and the way she is trying to make this about something that it isn't," Sanders said Wednesday. "This was a President who loves our country very much, who has the greatest level of respect for men and women in uniform and wanted to call and offer condolences to the family."
She added: "And I think to try to create something from that that the congresswoman is doing is frankly appalling and disgusting."
The Florida Democrat was in the car during the call and was the first to tell reporters that Trump offended the family during the call.
Sanders also said there is no recording of Trump's call with Johnson's widow
. Her husband was among the four soldiers killed in Niger.
Asked if there was a recording of the call, Sanders said: "No."
"No, but there were several people in the room from the administration that were on the call, including the chief of staff, John Kelly," Sanders said.
Wilson told reporters Tuesday night that Trump told Johnson's widow that "he knew what he signed up for, but I guess it still hurt."
Trump tweeted in response on Wednesday morning: "Democrat Congresswoman totally fabricated what I said to the wife of a soldier who died in action (and I have proof). Sad!"
Sanders said multiple people in the room for Trump's call believed the call was "completely respectful" and "very sympathetic."
Sanders did not get into why a congresswoman, who overheard part of the call on speakerphone, and a member of the family believe the President slighted the fallen soldier. She also slammed the media for trying to make the call "into something that isn't."
Sanders notably did not deny the content of what Wilson said, saying she would not get into specifics.
"I am not going to get into the back and the forth. I think the sentiment of the President was very clear, he took the time to make a call to express his condolences, to thank the family for this individual's service," she said. "I think it, frankly, is a disgrace of the media to try to portray an act of kindness like that."