In his first address to the French public, Snowden said that the world cannot accept efficiency as an excuse to commit "inexcusable crimes."

Speaking from Russia where he has been granted asylum, Snowden made his first public appearance in France by video conference as part of Amnesty International's celebration of the International Day of Human Rights. 

"Efficiency has no place in the debate about right and wrong," Snowden said. "The Senate’s report is a good step forward in terms of acknowledging the reality of what we have done. But this does nothing in terms of holding the officials who ordered this behavior and the officers who actually directly engaged in torture to account," he added.

The U.S. Senate Intelligence committee’s report summary detailed how the CIA used techniques such as waterboarding - simulating the sensation of drowning in a victim - mock execution, sexual threats and other forms of torture and degrading treatment against detainees who had been forcibly disappeared.

The effects of the techniques and detention conditions led to detainees suffering "hallucinations, paranoia, insomnia and attempts at self-harm and self-mutilation," the report revealed.

The 500-page document is an unclassified executive summary of a 6,700-page report that remains classified. It is the result of a more than five-year investigation into the CIA’s interrogation practices.

'Mass surveillance is practiced in all countries'

Snowden, 31, has been hailed as a hero around the world for exposing the mass global illegal surveillance activities employed by the U.S.' National Security Agency and the UK's GCHQ communications monitoring center.

Snowden's leaked files revealed that the NSA and GCHQ had spied on phone conversations of several international leaders, including Germany, Turkey, China and Russia.

"I do not have access to secret information. I destroyed everything, except what I gave to journalists. Now it is the role of the press. But mass surveillance takes place in all the countries that have the means to have intelligence agencies," the former American intelligence analyst said when he was asked if France is under surveillance. 

However, Snowden said that "There were reports that showed that Orange - a French multinational telecommunications corporation - provided information to the DGSE, France's external intelligence agency."

Snowden's leaks have scandalized Americans and Europeans but have led to little action by governments to rein in the activities of their intelligence-gathering services.

The Commissioner for Human Rights at the Council of Europe, Nils Muiznieks, warned on Monday that mass surveillance conducted by intelligence agencies, including the UK's, could not be justified by the so-called fight against terrorism.

A survey of more than 23,000 people in 24 countries released last month by Canadian research group Centre for International Governance Innovation found that while 62 percent of Americans were more concerned about online privacy than they were a year ago, only around a third have done anything to better protect their data.

Half of the Europeans surveyed were concerned about their data online, and 29 percent have taken steps to improve their online security.   

"I would love to go back to the United States. This is my home," Snowden said, adding that he would also like to live in Western Europe. 

Snowden, who received a three-year residence permit from Russia in August 2014, is wanted in the U.S. for "espionage, theft and conversion of government property."