"Mass surveillance has no proven track record and it should not be a part of our [US] policy," Snowden said Friday during a Cato Institute surveillance conference via a video-link from Russia, stressing that the practice "should not be pursued, it should not be funded because it takes resources away from methods and mechanisms in investigations that we know work and that we know are effective".
The whistleblower also argued that mass surveillance is particularly ineffective in the context of terrorism and that human sources are often the best way to prevent terrorist attacks.
"They [the US government] made us think that these individuals [terrorists] were not associated with terrorism despite the fact that we had intelligence from human sources….we [the United States] didn't do a good job," the whistleblower added.
Snowden's video appearance at the Friday security conference follows the release of the US Senate Intelligence Committee's report that outlines the CIA's detention and interrogation techniques used on alleged al-Qaeda terrorists after the 9/11 attacks in New York and Washington DC.
The Senate report has sparked worldwide international reproach. However, the US Department of Justice (DOJ) says that despite the use of torture that did not bring any results, as outlined in the report, the DOJ will not launch an investigation into the CIA torture claims.