The American National Security Agency (NSA) is preparing to release details of foiled terrorist plots to highlight the importance of bulk data surveillance.
Senator Dianne Feinstein, chair of the Senate intelligence committee, said General Keith Alexander, director of the NSA, is preparing to release details of cases where the surveillance "has stopped a terrorist attack, both here and in other places".
Had the programmes been in place at the time, they could have foiled 9/11
Details could be forthcoming as early as Monday, the Guardian reports.
The unusual step has been taken in light of two revelations regarding the NSA's spying activities.
On 6 June, it was revealed the agency was collecting smartphone data on hundreds of US telco Verizon's customers. The following day, the existence of the PRISM programme was revealed, which, it is alleged, gives the NSA direct access to the servers of a number of internet companies, including Microsoft, Google and Facebook.
These three companies have subsequently asked for permission for requests under PRISM to be made public, claiming reports the NSA is given unfettered access to servers through the programme are untrue.
The NSA is yet to respond to these requests.
Opinion in the US is divided over PRISM, although not along party lines. Members of both the Democrat and Republican parties have condemned the programme, while others have spoken out in favour of it.
However, amongst the intelligence community, those who have spoken up about it have been supportive.
FBI director Robert Mueller strongly defended both the PRISM and Verizon programmes, telling the House judiciary committee that, had they been in place at the time, they could have foiled the 9/11 terror plot.
Even so, members of the committee questioned its effectiveness, asking why it did not stop the Boston marathon bombing. Nevertheless, Mueller contested that if the scope of such broad-based surveillance programmes were narrowed "you narrow the dots and that dot might be the dot that prevents the next Boston".
Questions have also been raised about the relationship between GCHQ and the NSA with regards to the sharing of intelligence gleaned through PRISM, with suggestions the UK Government listening post may have used it as a legal loophole to spy on British citizens.
Foreign Secretary William Hague has refused to confirm or deny GCHQ's involvement, but has insisted the agency has broken no laws.
