More than 1 million people from around the world have signed a petition urging President Barack Obama to pardon whistleblower Edward Snowden before he leaves office on 20 January.

Proponents of the Pardon Snowden campaign, which include Amnesty International, the American Civil Liberties Union and the Human Rights Watch among other human rights groups, said the petition was delivered to the White House on Friday, arguing that Snowden's actions "set in motion the most important debate about government surveillance in decades."

"People from all over the world have come together to show their support for Edward Snowden and thank him for the public service he performed in standing up for their human rights," Salil Shetty, Amnesty International's Secretary General, said in a statement. "Edward Snowden is a hero, not a traitor, and that he remains in limbo years after sparking such an important global debate about surveillance and privacy is a gross injustice. He deserves better than a life in exile.

"By pardoning Snowden, President Obama would place himself on the right side of history, and demonstrate that he stands with those who fight for what is right, even at great personal cost," Shetty said.

In 2013, the former NSA contractor leaked a trove of classified files to reporters, revealing the scale of mass surveillance programmes in the US and the UK. Since then, Snowden has been residing in Moscow to avoid extradition to the United States where he faces charges under the 1917 Espionage Act that could land him in prison for up to 30 years, if convicted.

The massive leaks also sparked an important public debate on government surveillance, privacy, data protection and human rights and led to legislative reform.

Pardon Snowden
A balloon bearing the effigy of former US intelligence contractor Edward Snowden is seen attached to the Statue of Liberty replica by French sculptor Auguste Bartholdi during an action organized by Amnesty International in Paris. Eric Feferberg/AFP/Getty Images

Launched in September 2016 by multiple human rights groups, the Pardon Snowden campaign has garnered the support of numerous scholars, intelligence experts, actors and human rights advocates. Some notable signatories who have thrown their support behind the campaign include Apple co-founder Steve Wozniak, Twitter CEO Jack Dorsey, Open Society Foundations founder and chair George Soros, Pentagon Papers whistleblower Daniel Ellsberg and actors Mark Ruffalo, Maggie Gyllenhaal among others.

"When the internet first came along, we thought it was going to be a beacon of freedom, sharing and learning," Wozniak said. "Edward Snowden showed us that the internet was actually being used by governments and companies to monitor us and invade our privacy.

"He gave up his whole life to stand up against secret spying and for the Constitution. That's why he's a hero, and it's why he deserves a pardon."

In November, former staff members of the Church committee, a Watergate-era intelligence watchdog group, also called on Obama to extend leniency to Snowden, arguing that although Snowden's disclosures were illegal, they did spur positive reform. They also noted earlier cases of leniency shown by Obama's and previous administrations towards others that violated the same law.

Ben Wizner, an ACLU attorney working on behalf of Snowden said "taking action while it's still possible would send a powerful signal to the world, in troubled times, that many Americans are still committed to human rights and democratic principles."

However, President Obama has suggested earlier that he would not likely grant Snowden clemency saying he "can't pardon somebody who hasn't gone before a court."

In December, the president granted clemency to 231 people - the most in a single day by any US president in history. He has commuted the sentences of 1,176 individuals, including 395 life sentences, and granted pardons to 78 people.

Earlier this week, Snowden called on Obama to pardon fellow whistleblower Chelsea Manning over himself saying "you alone can save her." Manning is currently serving a 35-year-sentence for leaking classified military documents and sensitive information to WikiLeaks. One day later, WikiLeaks founder Julian Assange said he would accept extradition to the US if Obama grants Manning clemency "despite clear unconstitutionality of DoJ case."