President Donald Trump regrets not firing former FBI director, James Comey, earlier.

In an interview with the Hill, Trump said he should have fired Comey "right after the [Republican] convention" — even though he would have only had the power to do so once he became President.

"I would have been better off firing him or putting out a statement that I don't want him there when I get there," said Trump.

President Donald Trump displayed a deep misunderstanding of his own authority Tuesday, bemoaning that he didn't fire FBI Director James Comey back when he won the Republican primary, or at least after the Republican convention, in an interview with the Hill.

Barack Obama was still President during both of those events and vested with the power to fire Comey.

"If I did one mistake with Comey, I should have fired him before I got here. I should have fired him the day I won the primaries," Trump told the Hill. "I should have fired him right after the convention, say I don't want that guy. Or at least fired him the first day on the job. I would have been better off firing him or putting out a statement that I don't want him there when I get there."

Trump also mentioned that he is ordering the declassification of documents related to the Russia probe because exposing it as a partisan "hoax" would be a "crowning achievement" of his presidency.

"I hope to be able to call this, along with tax cuts and regulation and all the things I've done … in its own way this might be the most important thing because this was corrupt," he added to the Hill.

He went on to say that his own FBI is working against him and trying to undermine his presidency.

"What we have now is an insurance policy," the Trump told the Hill. "But it has been totally discredited, even Democrats agree that it has been discredited. They are not going to admit to it, but it has been totally discredited. I think, frankly, more so by text than by documents."

He concluded that he hoped to "expose" the FBI as "truly a cancer in our country."