US President-elect Donald Trump has reacted furiously to allegations that Russia has compromising material on him, saying Moscow has "never tried to use leverage on me".
Mr Trump condemned US intelligence agencies for allowing "fake news" to "leak" into the public, asking: "Are we living in Nazi Germany?"
The claims say his election campaign communicated with Moscow and also contain suggestions of prostitute use.
Russia also angrily denied the claims.
Dmitry Peskov, President Vladimir Putin's spokesman, said the allegations were "pulp fiction" and a "clear attempt to damage relations".
In a series of tweets, Mr Trump said: "Russia has never tried to use leverage over me. I HAVE NOTHING TO DO WITH RUSSIA - NO DEALS, NO LOANS, NO NOTHING!
"I win an election easily, a great "movement" is verified, and crooked opponents try to belittle our victory with FAKE NEWS. A sorry state!
"Intelligence agencies should never have allowed this fake news to "leak" into the public. One last shot at me. Are we living in Nazi Germany?"
Mr Trump is due to hold his first news conference as president-elect later on Wednesday.
Last week, US intelligence agencies reportedly presented the new claims - in the form of a two-page synopsis - to the president-elect, to President Barack Obama and to congressional leaders, CNN said on Wednesday.
The 35-page dossier of memos was published in full by Buzzfeed.
In the same briefing last week, US intelligence agencies released another unclassified report saying Russia ran a hacking campaign to influence the US presidential elections.
The latest allegations say Russia has damaging information about the president-elect's business interests, and salacious video evidence of his private life, including claims of using prostitutes at the Ritz-Carlton hotel in Moscow.
Other claims included in the 35-page dossier suggest Trump aides were involved with the alleged Russian hack of the Democratic Party of his rival Hillary Clinton.
Michael Cohen, a lawyer to Mr Trump named in the memos, has denied a specific claim that he went to Prague in August or September 2016 to meet Kremlin representatives to talk about the hacking.
"I've never been to Prague in my life. #fakenews," he tweeted.
Reince Priebus, Mr Trump's chief of staff, called the dossier report "phoney baloney garbage".
US media suggest the videos were prepared as "kompromat" - compromising material collected about a politician or public figure in order to create a threat of negative publicity, if needed.
The allegation that Mr Trump was vulnerable to blackmail and was being manipulated financially or otherwise is astonishing, says the BBC's Paul Wood in Washington.
In a campaign that was unprecedented, this goes to new extremes, our correspondent adds.
How this came to light
The allegations began circulating in political and media circles in recent months.
The BBC understands they are based on memos provided by a former British intelligence officer for an independent organisation opposed to Mr Trump in Washington DC. Sources say the CIA regards them as "credible".
The original intention was to derail Mr Trump's candidacy, reports say.
The BBC first saw the documents in October but has been unable to verify the claims included. Several material inaccuracies have been highlighted in them.
However past work by the British operative was considered by US intelligence to be reliable, US media say.
The existence of the documents was first reported by Mother Jones in October.
What we know already about Russia hacking claims
US spy agencies say Russia was behind the hacking of Democratic Party emails during the presidential campaign.
They say the order came from the Kremlin to sway the election for Mr Trump and away from Mrs Clinton.
But so far Mr Trump has failed to explicitly agree with the conclusions of the intelligence services. And he has condemned those who oppose good relations with Russia as "fools".
Russia has denied any involvement in the hacks and accused the US of conducting a witch-hunt.