Veteran US political operative Roger Stone ridiculed the probe into Russian election interference and attacked Congress and the intelligence community Tuesday in testimony to lawmakers.

Stone, who began his career as a political trickster for Richard Nixon and claims credit for pushing Donald Trump to run for president, lashed out at the committee for spreading "lies" in a written statement ahead of his closed-door testimony.

After more than three hours speaking with the House Intelligence Committee, which has access to top-secret information on Russian activities from intelligence bodies, he said his view had not changed.

"I think it's an entirely political exercise," he told reporters in the halls of Congress outside the committee room.

Stone, who had earlier lashed out at specific members of the committee, one of three in Congress investigating the alleged Russian election meddling, said the discussion was "productive" and "pretty collegiate".

The dapper 65-year-old, a behind-the-scenes tactician for a long series of Republican political campaigns, taunted the committee before heading to Congress early Tuesday.

"Never pass up a chance to have sex, be on television or testify before a House Congressional Committee," he said in a tweet.

He followed that with a tweeted photograph in the Trump International Hotel in Washington Monday evening with a huge martini glass, and another holding a classic 1976 tome, "The Russians" by Hedrick Smith, quipping: "Preparing for my testimony."

But, facing a hearing in which he had to testify under oath for the first time, his prepared statement took serious aim at allegations that he had communications with Russian hackers and WikiLeaks.

"I view this as a political proceeding because a number of members of this committee have made irresponsible, indisputable and provably false statements in order to create the impression of collusion with the Russian state," he said.

"I do not engage in any illegal activities on behalf of my clients or the causes which I support."

"There is one 'trick' that is not in my bag and that is treason."

- Intel on Russia 'politicized' -

He also said the US intelligence community has not provided evidence of their conclusion that Russians boosted Trump's presidential campaign and that the two sides colluded.

"Our intelligence agencies have been politicized," he said

Stone said he did not tell the committee who his journalist go-between was in contacts with Wikileaks during the election campaign. Stone has been accused publicly but not formally of having collaborated with the anti-secrets group in its release of stolen Democratic Party communications and documents.

He said he would ask the journalist for "release" to be able to provide their identity to investigators, but before that he would remain true to his promise of confidentiality.

"I'm not going to burn somebody I spoke to off the record," he said.

Meanwhile Stone said that Trump's former presidential campaign chief Paul Manafort expects to be indicted in the probe over Russian election meddling.

"His attorneys informed my attorneys of that," Stone, a longtime friend of Manafort, told reporters.

However, he added, "They seem to know neither when or what the charge may be."

 Source: AFP