Two U.S. officials with direct knowledge told NBC News on Tuesday that briefing materials prepared for President-elect Donald Trump included information that initially circulated among Trump opponents and was passed to U.S. intelligence agencies making damaging allegations about his dealings with Russians.

Neither of the officials said the FBI was actively investigating the information, which has not been verified by U.S. agencies.

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The sources would not comment on the nature of the allegations. The Trump transition team did not immediately respond to a request for comment.

But Trump himself did tweet at 8:19 p.m. ET Tuesday, in all caps, "FAKE NEWS — A TOTAL POLITICAL WITCH HUNT!"

FAKE NEWS - A TOTAL POLITICAL WITCH HUNT!



It wasn't completely clear exactly what he was referring to, but other news outlets had already reported on the briefing materials.



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Appearing Tuesday evening on NBC's "Late Night with Seth Meyers," Trump adviser Kellyanne Conway dismissed the reports as having possibly originated with a Russian investigator or groups that wanted Hillary Clinton to win the election.

And in an interview with NBC News before his farewell address Tuesday night in Chicago, President Barack Obama said he had not seen the news accounts of Trump's Russian ties but noted that "as a matter of principle and national security, I don't comment on classified information."