WASHINGTON: A senior lawmaker from President Barack Obama's Democratic party has compared US intelligence leaker Edward Snowden with Mahatma Gandhi , saying the controversial whistleblower was engaged in a "non-violent" act of "civil disobedience".

John Lewis , one of America's most revered civil rights leaders, says Snowden, who has come in for some harsh criticism from Obama Administration for leaking details of classified surveillance programmes, was continuing the tradition of civil disobedience.

"In keeping with the philosophy and the discipline of non-violence, in keeping with the teaching of Henry David Thoreau and people like Gandhi and others, if you believe something that is not right, something is unjust, and you are willing to defy customs, traditions, bad laws, then you have a conscience. You have a right to defy those laws and be willing to pay the price," Lewis told the Guardian newspaper.

His comments came on the same day Obama cancelled his scheduled meeting with Russian counterpart Vladimir Putin after Moscow granted temporary asylum to the 30-year-old former CIA contractor.

Lewis, the man whom Obama called the 'conscience of the US Congress', said Snowden could claim he was appealing to "a higher law" when he disclosed top secret documents showing the extent of NSA surveillance of both Americans and foreigners.

73-year-old congressman and one of the last surviving lieutenants of Martin Luther King said Snowden was "engaged in an act of civil disobedience".

"That is what we did," he added. "I got arrested 40 times during the sixties. Since I've been in Congress I've been arrested four times. Sometimes you have to act by the dictates of your conscience. You have to do it."

Lewis was among the majority of Democratic congressmen who voted for an amendment in the House of Representatives last month that sought to effectively end the NSA's bulk collection of millions of phone records.

The vote was narrowly defeated, but revealed a surprising degree of congressional opposition to the spy agency's collection of data.

Snowden, who passed highly-classified documents to the Guardian and Washington Post, has argued he was acting out of conscience because he wanted to shine a light on a surveillance apparatus which he believes is out of control.

The US insists that Snowden is not a whistleblower, but a felon who should be returned to America from Russia, where last week he was granted temporary asylum after spending over a month at the Moscow Airport.