Russian president Vladimir Putin has accused the outgoing US administration of trying to undermine Donald Trump by spreading fake allegations and said those who are doing it are "worse than prostitutes".
The statement reflected the Kremlin's boiling anger at President Barack Obama's administration, which declined to comment on Mr Putin's accusation.
Asked about an unsubstantiated dossier outlining unverified claims that Mr Trump engaged in sexual activities with prostitutes at a Moscow hotel, Mr Putin dismissed it as "fake" and "nonsense" and said it was part of efforts by Mr Obama's administration to "undermine the legitimacy of the president-elect" despite his "convincing" victory.
Mr Trump earlier rejected the sexual allegations as "fake news" and "phony stuff".
Mr Putin's broadside at the White House reveals a culmination of tensions between Moscow and Washington, which have built up over the Ukrainian crisis, the Syrian war and the allegations of Russian meddling in the US election.
"People who order such fakes against the US president-elect, fabricate them and use them in political struggle are worse than prostitutes," he said.
"They have no moral restrictions whatsoever, and it highlights a significant degree of degradation of political elites in the West, including in the United States."
He spoke in Moscow during a news conference following talks with the president of Moldova.
The Russian leader ridiculed the authors of the Trump dossier for alleging that Russian spy agencies were collecting compromising material on Mr Trump when he visited Moscow in 2013 for the Miss Universe pageant.
"He wasn't a politician, we didn't even know about his political ambitions," Mr Putin said.
"Do they think that our special services are hunting for every US billionaire?"
Mr Putin also sarcastically suggested that Mr Trump, who met the world's most beautiful women at the pageant, had a better choice for female companionship than Moscow prostitutes, even though Mr Putin claimed "they are also the best in the world".
He said Mr Trump's foes are ready to go as far as to "stage a Maidan in Washington to prevent Trump from entering office", in reference to the alleged US role in organising protests in the main square of the Ukrainian capital, the Maidan, which forced the nation's Russia-friendly president from power in 2014.
"People who are doing that are inflicting a colossal damage to the interests of the United States," Mr Putin said.
He also charged that those spreading allegations against Mr Trump want to "bind the president-elect hand and foot to prevent him from fulfilling his election promises".
"How can you do anything to improve US-Russian relations when they launch such canards as hackers' interference in the election?" he said.
Mr Putin voiced hope that "common sense will prevail" and Russia and the United States will be able to normalise their relations once Mr Trump takes office on Friday.
He said he does not know Mr Trump and has no interests in defending him.
"I don't know Mr Trump. I have never met him and I don't know what he will do on the international arena," Mr Putin said.
"I have no reason whatsoever to assail him, criticise him for something, or defend him."
At a separate news conference on Tuesday, Russian foreign minister Sergey Lavrov said Moscow hopes for better relations with the United States based on respect for mutual interests once Mr Trump takes office, in contrast with the "messianic" approach of the outgoing US administration that he said has ravaged ties.
Mr Lavrov said Russia and the United States can reach common ground on nuclear arms control and other issues if each country proceeds from its national interests and shows respect for the other side.
He voiced hope that Mr Trump's team will consist of pragmatic people "who will not engage in moralising and will try to understand the interests of their partners just as they clearly uphold their own interests".
Mr Lavrov denounced the foreign policies of the outgoing Obama administration and its allies as "messianic" attempts to enforce Western values on the rest of the world, which has led to instability and conflicts in the Middle East and elsewhere.
He said Moscow is inviting representatives of the incoming US administration to attend talks on Syria in Kazakhstan on Monday, discussions brokered by Russia, Turkey and Iran.
He voiced hope that Russian and US experts could start discussions on fighting terrorism in Syria during that meeting.
Asked to comment on Mr Trump's recent remarks in which he indicated he could end sanctions imposed on Russia in the aftermath of its 2014 annexation of Crimea in return for a nuclear arms reduction deal, Mr Lavrov said Russia was ready to sit down for nuclear arms talks with the US.
He noted he did not see Mr Trump's words as an offer to cut arms in exchange for cancelling the sanctions, rather as an expression of readiness to look at reviewing the sanctions while engaging in negotiations on arms control, among other issues.
Mr Lavrov added that, along with nuclear arsenals, the agenda for such negotiations should include new hypersonic weapons, missile defence, the weaponisation of space and other issues.
Like Mr Putin, Mr Lavrov rejected allegations of Russian meddling in the US election as "absurdities" and "fakes" intended to hurt Mr Trump.
He said US intelligence agencies have failed to produce any evidence to back those claims, adding that officials who engaged in the effort "deserve to be fired, as they receive their salaries for nothing".
Mr Lavrov described the allegations of Russian election meddling in the US vote as the final "spasms of those who realise that their time is coming to an end".
"The time of foreign policy demagogues is over, and, feeling hurt, they fabricate all kinds of fakes," he said.
"First, officials leak fakes to the media, then media start spinning them and, finally, officials comment on them as facts."
Mr Lavrov also denounced a dossier on Mr Trump compiled by a former British spy as a "rude provocation", contemptuously referring to its author as a "runaway swindler from MI6" without citing his name.
In a reflection of the bad blood between Mr Obama's administration and the Kremlin, Mr Lavrov accused US officials of making repeated attempts to recruit Russian diplomats in the United States as spies, including a deputy chief of mission.
He called the attempts "cynical" and "unprecedented".