Trump says congresswoman 'totally fabricated' story that he told a soldier's widow 'he knew what he signed up for'

President Donald Trump denied Florida Rep. Frederica Wilson's claim that he told the wife of a soldier slain in an attack on US forces in Niger that the soldier "knew what he signed up for."

"Democrat Congresswoman totally fabricated what I said to the wife of a soldier who died in action (and I have proof). Sad!" Trump tweeted Wednesday morning.

Wilson told local ABC affiliate WPLG that when Trump spoke to Myeshia Johnson - the widow of Sgt. La David Johnson, one of the four US Army Special Forces troops killed in action during a mission in the African country of Niger earlier this month - Trump said, "He knew what he signed up for ... but when it happens, it hurts anyway."

"It's so insensitive. He should have not have said that. He shouldn't have said it." Wilson told later CNN's Don Lemon.

Wilson claimed to have overheard Trump say it as she rode with Johnson on the way to the airport to receive the fallen soldier's body.

Bryan Logan contributed to this report.