Nigel Farage is a "person of interest" in the ongoing US investigation into Russian involvement in Donald Trump's presidential campaign, according to The Guardian.

The paper says sources close to the investigation have told its reporters that Farage's relationship with Trump's team, as well as with Wikileaks founder Julian Assange, mean he may possess information pertinent to the inquiry.

Last year in the 2016 US presidential election, WikiLeaks published a number of hacked emails which dented the campaign of Democratic candidate Hillary Clinton.

The site is suspected to have worked with Russia via third parties to obtain the emails, according to testimony in Congress by former CIA director John Brennan.

The Guardian claims sources told the paper it was the closeness of the former UKIP leader to the people involved in the probe which a specific focus of the investigation.

There is no suggestion Farage is a suspect or a target in the investigation, and a spokesman has categorically denied he has been involved with Russian officials.

The spokesman for the former UKIP leader said the accusations made in The Guardian are "hysterical."

He said: "In response to the Guardian article, it has taken me a long time to finish reading because I am laughing so much.

"This hysterical attempt to associate me with the Putin regime is a result of the liberal elite being unable to accept Brexit and the election of President Trump.

"For the record I have never been to Russia, I've had no business dealings with Russia in my previous life and I have appeared approximately three times on [Russia Today] in the last 18 months.

"I consider it extremely doubtful that I could be a person of interest to the FBI as I have no connections to Russia.

"My meeting with Julian Assange was organised for me by LBC Radio with a view to conducting an interview."

More to follow.