President Donald Trump's firing of James Comey as FBI director threatens the independence of America's top law enforcement agency, a former FBI official told CNBC.

"This is not going to end well for this administration," the former official said.

"[Trump] is out of control," the former official continued, adding that what the president has done "goes against core American values."

@EamonJavers: 1. I just spoke to a former high ranking FBI official about the president's Tweets. Here is what he said...

@EamonJavers: 2. Former FBI official on Trump: "First he started a war with the intelligence agencies, and now he wants one with the FBI?"

@EamonJavers: 3. Former FBI official: "This is not going to end well for this administration."

@EamonJavers: 4. Former FBI official on Trump: "He is out of control. It is so out of the norm for him to even say that."

@EamonJavers: 5. Former FBI official on Trump: "This threatens the independence of the FBI and goes against core American values."

In an exclusive interview with NBC News, Trump said Thursday he decided to fire Comey on his own, before Deputy Attorney General Rod Rosenstein's memo that harshly criticized Comey's actions and suggested he should be removed.

White House press statements, though, are creating confusion regarding the timeline of Comey's firing within the FBI. For example, White House press secretary Sean Spicer has said the president fired Comey because he was advised to do so.

Trump took to Twitter on Friday to blame his "active" presidency for any inaccuracies that his surrogates make at the podium. Maybe, Trump said, he will just cancel briefings with the media altogether.

@realDonaldTrump: ...Maybe the best thing to do would be to cancel all future "press briefings" and hand out written responses for the sake of accuracy???