Donald Trump has dismissed as “fake news”, claims that Russia officials had developed compromising and embarrassing information about him in an attempt to exert influence over him.

In a tweet written entirely in capital letters, the President-elect said: “Fake news – a total political witch hunt.” For now, he provided no other details, or evidence.

The blunt comment came amid a flurry of reports that said senior US intelligence officials last week presented to both President Barack Obama and Mr Trump, a summary of unconfirmed reports that said Russia had collected compromising and salacious personal information about the 70-year-old Republican.

Reports said the information suggested that the Russian authorities had for several years looked to influence Mr Trump. They also claim that Russia was able to put together compromising information, or “kompromat”, against him.

CNN was the first to report the developments, and said the information that was collated by intelligence officials was based on memos created by political operatives opposed to Mr Trump’s candidacy. Details of the reports began circulating in government and media circles last autumn and Mother Jones magazine reported at the time that US officials were trying to assess the validity of the information.

The two-page summary, details of which were first reported by CNN, was presented as an appendix to the intelligence agencies’ report on Russian hacking efforts during the election. Reuters said the allegations partly came from memos put together by a former British intelligence operative.

Trump chief adviser Kellyanne Conway denies compromising claims against President-elect

The former agent’s company was paid, firstly by Mr Trump’s Republican rivals and later by supporters of his Democratic opponent, Hillary Clinton.

It said the FBI was investigating is still assessing the credibility and accuracy of the allegations, which are based primarily on information from Russian sources, but has not confirmed many essential details in the memos about Mr Trump.

One reason the US intelligence chiefs took the step of including the synopsis in the briefing documents was to make Mr Trump aware that allegations about him are circulating among intelligence agencies, senior members of Congress and government officials, CNN said.

An unclassified intelligence report released last Friday concluded that Russian President Vladimir Putin ordered an effort to help Mr Trump’s electoral chances by discrediting Democrat Hillary Clinton in the 2016 campaign.

The report said US intelligence agencies have concluded that as part of the effort Russia's military intelligence agency, the GRU, used intermediaries such as WikiLeaks and others to release emails it hacked from the Democratic National Committee and top Democrats.

FBI Director James Comey on Tuesday refused to say whether his bureau was investigating any possible ties between Russia and the Trump presidential campaign, citing policy not to comment on what the FBI might or might not be doing.

The Associated Press said that Mr Comey testified at the Senate’s second hearing in a week addressing allegations of Russian election hacking. In late October he angered Democrats when he announced 11 days before the election that the FBI was looking at more emails as part of its investigation of Hillary Clinton.