President Trump on Monday escalated his feud with former President Obama, insisting during a news conference that his predecessor committed a “crime” but refusing to dive into details.

When asked by a reporter in the Rose Garden what crime he is accusing Obama of committing, Trump responded: “Obamagate, it’s been going on for a long time, it’s been going on from before I got elected, and it's a disgrace that it happened. You look at now all of this information that’s being released and from what I understand that’s only the beginning.”

When pressed for details, the commander in chief told a Washington Post reporter, "You know the crime. The crime is very obvious to everybody. All you have to do is read the newspapers, except yours."

Trump on Sunday quoted a tweet that accused Obama of using “his last weeks in office to target incoming officials and sabotage the new administration.”

An error occurred while retrieving the Tweet. It might have been deleted.

“The biggest political crime in American history, by far!” Trump added, later tweeting, “OBAMAGATE!”

On Friday, Obama weighed in on the FBI controversy surrounding former national security adviser Michael Flynn, declaring the “rule of law is at risk” after the Justice Department moved to drop the charges against the former national security adviser. At the same time, new details emerged about what the former president knew about the case against Flynn in the last days of his administration.

TRUMP UPS ATTACK AGAINST OBAMA WITH 'OBAMAGATE' TWEET

“The news over the last 24 hours I think has been somewhat downplayed -- about the Justice Department dropping charges against Michael Flynn,” Obama said, according to Yahoo! News, in a web talk with members of the Obama Alumni Association.

“And the fact that there is no precedent that anybody can find for someone who has been charged with perjury just getting off scot-free," Obama reportedly said. "That’s the kind of stuff where you begin to get worried that basic -- not just institutional norms -- but our basic understanding of rule of law is at risk."

Yahoo! News, in reporting the tape, noted that Obama incorrectly states the charges against Flynn, who was not charged with perjury. Instead, Flynn pleaded guilty in 2017 to lying to the FBI about his conversations with the Russian ambassador in the transition period between the Obama and Trump administrations. Flynn has since tried to withdraw his guilty plea, citing "bad faith" by the government.

OBAMA WHITE HOUSE MAY HAVE SEEN 'OPPORTUNITY TO DISRUPT' FLYNN, EX-FBI OFFICIAL SAYS

Obama has long had a tense relationship with Flynn: He fired him as head of the Defense Intelligence Agency in 2014 and warned the Trump administration against his hiring.

Documents released Thursday revealed Obama was aware of the details of then-incoming national security adviser Michael Flynn's intercepted December 2016 phone calls with then-Russian Ambassador Sergey Kislyak.

Obama's unexpectedly intimate knowledge of the details of Flynn's calls, which the FBI acknowledged at the time were not criminal or even improper, raised eyebrows because of his own history with Flynn -- and because top FBI officials secretly discussed whether their “goal" was "to get [Flynn] to lie, so we can prosecute him or get him fired” when they interviewed him in the White House on January 24, 2017.

Flynn’s attorney Sidney Powell told Fox News’ “Sunday Morning Futures,” that she too believed the FBI scandal reached up to Obama.

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“The whole thing was orchestrated and set up within the FBI, Clapper, Brennan and in the Oval Office meeting that day with President Obama,” Powell said.

Fox News' Gregg Re and Adam Shaw contributed to this report.