Edward Snowden says will vote in US presidential election

Edward Snowden, in exile in Moscow after leaking US National Security Agency documents, said on Friday he intends to vote in the US presidential election, but did not say which candidate he favours.

"I will be voting," Snowden said, speaking at a conference in Athens by video link from Moscow.

"But as a privacy advocate I think it's important for me ... That there should never be an obligation for an individual to discuss their vote. And I won't be doing so with mine."

He added: "What I will say about the candidates is that I'm disappointed we're not hearing much about the constitution in this election cycle. We're not hearing very much about our rights."

The 33-year-old spoke ahead of the opening of the movie "Snowden," starring Joseph Gordon-Levitt.

Snowden thanked human rights groups for their campaign to seek a pardon for him from President Barack Obama.

"I'm not actually asking for a pardon myself because I think the whole point of our system and the foundation of our democracy is a system of checks and balances," he said. "But ... I'm incredibly grateful and fortunate to be able to experience the support of the world's three leading human rights organisations."

A Republican-led bipartisan US House intelligence committee on Friday released a report calling Snowden a "serial exaggerator and fabricator" who doesn't fit the profile of a whistleblower.

All of the committee members separately sent Obama a letter urging him not to pardon Snowden, who revealed the NSA's collection of millions' of Americans phone records.

The American Civil Liberties Union, Human Rights Watch and Amnesty International are behind the campaign to pardon him.

Kenneth Roth, HRW's executive director, was on the panel of the Athens conference, and described the effort as "an uphill battle."

"What we're hoping is that after the election when Obama is in his final months in office at that stage he can begin to do something that are appropriate as a matter of conscience but politically difficult," Roth told the AP.

"One of them we would be is to pardon Snowden," he said. "There's been broad recognition that Edward Snowden has done an enormous public service by disclosing the degree to which all of our privacy has been invaded needlessly.