White House Deputy Press Secretary Sarah Huckabee Sanders asserted on Wednesday that President Donald Trump fired FBI Director James Comey because he committed "atrocities" against Hillary Clinton.

While standing in for Press Secretary Sean Spicer at Wednesday's press briefing, Sanders was grilled by reporters who clearly weren't buying the Trump's excuse for firing Comey.

"Director Comey has shown over the last several months and frankly over the last year a lot of missteps and mistakes," she insisted. "I think it's startling that Democrats aren't celebrating."

Fox News correspondent John Roberts noted that Trump had "celebrated" Comey before the election in October.

"He was a candidate for president, not the president," Sanders opined, adding that Comey was guilty of "atrocities" with regard to a press conference criticizing Clinton.

Watch the video below.