The New York Times reported on Friday that the FBI opened the investigation after Trump's firing of FBI Director James Comey raised concerns that the president posed a threat to national security. Since the report emerged, Trump attacked the FBI and the Times but he did not issue a specific denial about working with Russia until Monday.
"Not only did I never work for Russia, I think it's a disgrace that you even asked that question because it's a whole big fat hoax," Trump told reporters as he left the White House for a trip to Louisiana.