Earlier this month, NSA chief defended the surveillance programme, Prism.
The US National Security Agency (NSA) chief, Keith Alexander, has provided new details about Prism surveillance programme, claiming that it helped to thwart 54 terror plots.
Alexander said the NSA/CSS work force has executed its national security responsibilities with equal and full respect for civil liberties and privacy.
"The issue is one that is partly fueled by the sensational nature of the leaks and the way their timing has been carefully orchestrated to inflame and embarrass," Alexander said.
"The challenge of these leaks is exacerbated by a lack of public understanding of the safeguards in place and little awareness of the outcomes that our authorities yield."
Out of the total 54 plots, 42 are reported to be disruptive plots while the remaining 12 are related to terrorism.
Edward Snowden, a former Central Intelligence Agency employee, leaked the Prism programme details to the Guardian and the Washington Post.
Recently, the US warned countries in the Western Hemisphere that Snowden may travel to their countries or take asylum and urged them not to allow the ex-spy agency contractor proceed in further international travel, unless it is to the USA.