Donald Trump has suggested US intelligence agencies are Nazis in a row over a leaked dossier containing embarrassing claims reportedly compiled by a retired British spy.
The president-elect said there was a "political witch-hunt" after the US media ran unsubstantiated allegations that Russia is sitting on compromising material about the billionaire.
Intelligence officers briefed the Republican and President Barack Obama about the contents of the document last week and reports emerged last night on CNN.
Kremlin spokesman Dmitry Peskov said the reports were "complete fabrication and utter nonsense" and said the Russian government "does not engage in collecting compromising material".
President-elect Trump said intelligence agencies should not have allowed the "fake news" to leak, adding "are we living in Nazi Germany?"
The New York Times said the dossier had been drawn up by a former British intelligence officer with extensive experience of Russia during the presidential race. It is said to have been funded by opponents of his White House bid, including Republicans.
After Moscow dismissed the claims, the president-elect sent out a series of angry tweets.
"Russia just said the unverified report paid for by political opponents is 'A COMPLETE AND TOTAL FABRICATION, UTTER NONSENSE.' Very unfair!" he wrote.
"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?"
Prime Minister Theresa May's official spokeswoman declined to comment on the Trump dossier.