Donald Trump says intelligence agencies may have leaked a dossier which contained claims that Russia has compromising intelligence about him.
The US President-elect said that if the agencies had leaked the unsubstantiated document to the media it would be a "tremendous blot on their record".
He also said the claims in the dossier - reportedly compiled by a retired British spy - were "nonsense" and "fake news".
It reportedly alleges Russia obtained compromising material on the billionaire during a stay in a five-star hotel in Moscow - including recordings of graphic sexual acts.
It was also said to have included allegations of ongoing contact between associates of Mr Trump and intermediaries for the Kremlin.
Russia has dismissed the claims as "utter nonsense".
"The Kremlin does not have compromising information on Trump," Russian President Vladimir Putin's spokesman Dmitry Peskov said.
The allegations have not been verified by intelligence chiefs but were considered sufficiently serious to be included in a highly classified report on alleged Russian interference in the US presidential election.
Speaking in his first news conference since winning the November contest, Mr Trump said Russia had been involved in hacking during the campaign.
"As far as hacking, I think it was Russia - but I think we also got hacked by other countires and other people.
"And I can say that when we lost 22 million names and everything else that was hacked recently, they didn't make a big deal out of that.
"That was something that was extraordinary - that was probably China.
"We had much hacking going on".
US officials have confirmed Mr Trump and President Obama received the two-page memo - believed to be a synopsis of more detailed reports compiled by a British former spy.
The documents - apparently gleaned from sources in Russia and the US - claim the Russian regime has been "cultivating, supporting and assisting" Mr Trump for at least five years.
They suggest Vladimir Putin ordered his operatives to provide intelligence on Mr Trump's opponents, including Hillary Clinton, in return for information on US-based Russian oligarchs.
Mr Trump also criticised Buzzfeed, who published the documents, calling the media outlet "a failing pile of grbage".
And he criticised CNN for also reporting the story, refuting a reporter for the netwoek who was at the press conference saying: "Your organisation's terrible - quiet, quiet".
"I'm not going to give you a question - you are fake news", he told CNN's senior White House correspondent Jim Acosta.
Donald Trump refuses to take a question from CNN's senior White House correspondent @Acosta https://t.co/LosQWNqS6N https://t.co/oI9qWnOiRa
— CNN Politics (@CNNPolitics) January 11, 2017
Tweeting after the press conference, Mr Acosta said his question was asked by a colleague.
Fortunately ABC's Cecilia Vega asked my question about whether any Trump associates contacted Russians. Trump said no.
— Jim Acosta (@Acosta) January 11, 2017
