Deputy AG Rosenstein developed case to fire Comey 'on his own,' White House says

Sanders said Rosenstein's words weren't "at the direction necessarily" of Trump.

Sanders also said Rosenstein's letter contained his "original thoughts" and its contents weren't "at the direction, necessarily," of President Trump.

Questions have arisen about the timing of Comey's firing amid an investigation into alleged contacts between Trump associates and Russian officials — allegations the administration has denied.

"He asked them to put that in writing, the conversation that they had on Monday," Sanders said. "The words that were written weren't at the direction, necessarily, of the president. Those were their own thoughts and ideas."

The White House announced Tuesday night that Comey was fired because of his handling of the FBI's investigation into Clinton's emails. In a letter made public by the White House, Trump informed Comey of the decision, citing the recommendations of Rosenstein and Sessions.

Rosenstein was so upset with the White House for pinning the firing on him that he was on the verge of resigning Wednesday, administration sources told ABC News.

"I'm not aware of his threatening to resign," Sanders said today on "GMA." "That's a question I would have to refer you to the Department of Justice."

Andrew McCabe, the FBI's deputy director, became its acting director after Comey's termination.