"Attorney General Jeff Sessions should stop this Rigged Witch Hunt right now," the president wrote in a post on Twitter. "Bob Mueller is totally conflicted, and his 17 Angry Democrats that are doing his dirty work are a disgrace to USA!"

Trump's tweet came before the trial of ex-campaign chief Paul Manafort entered its second day in federal court in Virginia. Manafort is being tried by Mueller's team.

The president's lawyer Rudy Giuliani said in a statement to NBC News Wednesday afternoon that the president "was expressing his opinion" and that "no Presidential order was issued or will be."