A former British spy reportedly tipped off US intelligence that Russian operatives are claiming to have compiled compromising information about Donald Trump, it emerged on Tuesday night.
The 
claims that Russia has potentially damaging information about Mr Trump were included in an addendum to a top secret report presented last week to the president-elect and to President Barack Obama, according to CNN.
According to the report, the British source informed the US that Russian operatives were claiming to have compromising personal and financial information about Mr Trump.
The FBI is now investigating the veracity of the Russian claims.
While intelligence sources told CNN they consider the former British agent’s past work credible, doubts were raised after Buzzfeed News published a full version of the agent’s disclosures .
They included factual errors, as well as allegations that Russia was aware of sexual perversion engaged in by Mr Trump during a visit to Moscow. According to Buzzfeed, the dossier was prepared for Mr Trump’s political rivals.
A two-page summary of the findings was included in a report on Russia’s interference in the US election which was shown to Mr Trump last week.
The director of national intelligence and the chiefs of the CIA, FBI and NSA all travelled to Trump Tower to brief Mr Trump on the report on Friday.
After the meeting Mr Trump for the first time accepted the possibility that Russia may have been behind the hacks of the Democratic National Committee and Hillary Clinton’s campaign chairman, but insisted that Russia’s efforts did not impact the election result.
He also emphasised the importance of warmer relations with Moscow.
James Comey, the FBI director, declined to answer when asked during a Senate hearing on Tuesday whether the FBI was conducting an investigation into ties between Mr Trump or his associates and Russia.
The Senate’s Foreign Relations Committee will hold a confirmation hearing for Rex Tillerson, Mr Trump’s nominee for be secretary of state, on Wednesday.
Senators from both parties have expressed concern about the former ExxonMobil chief executive’s close working relationship with key figures in the Kremlin during his time at the oil company.
While Mr Trump has said he will improve relations with Russia, the country’s relationship with the UK may be souring.
Russia has claimed Britain is launching an “official witch-hunt” against Mr Putin’s administration in an 800-word statement posted online on Tuesday by the country’s embassy in London.