LONDON - British politician Nigel Farage is a "person of interest" in the US counter-intelligence investigation that is looking into possible collusion between the Kremlin and Donald Trump's presidential campaign, The Guardian newspaper reported on Thursday (June 1).

Sources with knowledge of the investigation said the former leader of the far-right UK Independence Party (UKIP) had raised the interest of FBI investigators because of his relationships with individuals connected to both the Trump campaign and Julian Assange, the WikiLeaks founder whom Farage visited in March.

WikiLeaks published troves of hacked e-mails last year that damaged Hillary Clinton's campaign. It is suspected of having cooperated with Russia through third parties, according to recent congressional testimony by the former CIA director John Brennan.

Farage has not been accused of wrongdoing and is not a suspect or a target of the US investigation, the report said. But being a person of interest means investigators believe he may have information about the acts that are under investigation and he may therefore be subject to their scrutiny.

Farage told the Daily Mail: "I don't believe it, I have no connections. I have never been to Russia. I have never had any business dealings with Russia."

When asked about the Guardian report, a UKIP spokesman said it was absurd. "To my knowledge, the only serious Russian politician that Nigel has spent time with is Garry Kasparov," the spokesman said.

Farage, who has campaigned for decades for Britain to leave the European Union, was a vocal backer of Trump. He met Trump in New York just days after the election and attended the inauguration in Washington.