Donald Trump dismissed them as 'total fabrication' while the Kremlin called them 'fiction'.
But astonishing - and unverified - allegations about depraved sex acts in a Moscow hotel room, a five-year link to the Russian regime and property 'sweeteners' involving World Cup 2018 have caused shockwaves across the world.
The President-elect denounced the release of the outlandish 'dirty dossier' this morning after it was reported that he was told in a briefing Russia had compromising personal and financial information about him.
CNN reported that the material was based on memos compiled by a British intelligence operative who was considered 'credible' by the US intelligence community.
Released just days before Trump's inauguration, both the 70-year-old and the Kremlin have branded the claims 'fake'.
Here are some of the main allegations that surfaced in the explosive memo:
Dealings: The dossier apparently includes claims about Trump's financial dealings with Moscow. In 2013 he held his Miss Universe contest in the Russian capital
Lurid sex claims
The memo claims Russian authorities tried to 'exploit Trump's personal obsessions and sexual perversion' in order to compromise him.
The headline claim is that they arranged for him to stay in a Moscow hotel which was covered by secret FSB cameras.
The report states that in 2013 Trump hired prostitutes to urinate on the bed of the Presidential Suite at the Moscow Ritz Carlton, where he knew Barack and Michelle Obama had previously stayed.
It says: 'Trump's unorthodox behavior in Russia over the years had provided the authorities there with enough embarrassing material on the now Republican presidential candidate to be able to blackmail him if they so wished.'
Degrading acts in bed used by president: The extraordinary - and entirely unverified - allegations that Donald Trump ordered prostitutes to commit degrading sex acts in the Ritz-Carlton in Moscow are contained in a dossier drawn up by a former British spy
Part of the document is seen above. Click here to see the full document first published by Buzzfeed
The dossier claimed that the Russian regime had been 'cultivating, supporting and assisting Trump for at least five years'
The document states that Trump had declined 'sweetener' real estate deals in Russia that the Kremlin lined up in order to cultivate him.
The business proposals were said to be 'in relation to the ongoing 2018 World Cup soccer tournament'.
Russia 'cultivated' Trump for five years
The dossier claimed that the Russian regime had been 'cultivating, supporting and assisting Trump for at least five years'.
According to the document, one source even claimed that 'the Trump operation was both supported and directed by Russian President Vladimir Putin' with the aim being to 'sow discord'.
Kremlin overlord: Trump was told that Vladimir Putin was in possession of apparently incendiary material
According to the document, one source even claimed that 'the Trump operation was both supported and directed by Russian President Vladimir Putin' with the aim being to 'sow discord'
Putin 'wanted to cause divisions in the West'
The report claims that Russian President Vladimir Putin himself had endorsed moves to encourage 'splits and divisions in the West.
A dossier on Hillary Clinton
At one point the memo suggests Kremlin spokesman Dmitry Peskov 'controlled' another dossier containing compromising material on Hillary Clinton compiled over 'many years'.
But Peskov denied there was any such material
The memo stated that the dossier has been compiled since her husband Bill's presidency and that it 'comprised mainly eavesdropped conversations of various sorts rather than details/evidence of unorthodox or embarrassing behavior'.
Elsewhere in the document, it is claimed that Putin was 'motivated by fear and hatred of Hillary Clinton.'
At one point the memo suggests Krelim spokesman Dmitry Peskov 'controlled' another dossier containing compromising material on Hillary Clinton (pictured) compiled over 'many years'
Elsewhere in the document, it is claimed that Putin was 'motivated by fear and hatred of Hillary Clinton'
At one point the memo says there were reports of 'clandestine meetings' between Donald Trump's lawyer Michael Cohen and Kremlin representatives in August last year in Prague.
However, Trump's counsel Michael Cohen today spoke out against allegations that he secretly met with Kremlin officials.
In response to the report on Tuesday, Cohen tweeted a picture of the front of his passport writing: 'I have never been to Prague in my life.'
CNN is now reporting that the Michael Cohen in the report is not Trump's lawyer.