WATCH: Furious Trump erupts in the Oval Office over Roger Stone -- and says impeachment taught him 'Democrats are crooked'

President Donald Trump on Wednesday erupted over the alleged mistreatment of Roger Stone, his longtime political aide.

Trump railed against the prosecution of Stone, calling it a disgrace. "They ought to apologize," the president said.

Stone was convicted last year of lying to Congress, tampering with a witness and obstructing an investigation into whether the Trump campaign coordinated with Russian operatives.

Four federal prosecutors abruptly resigned from Stone's case on Tuesday after senior officials in the Department of Justice intervened on his behalf an sought a less sentence.

Trump was also asked if he planned to pardon Stone.

"I don’t want to say yet," he replied.

Asked what being impeached had taught him, Trump said he learned that "the Democrats are crooked. They got a lot of crooked things going. That they’re vicious."

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