The NSA has the technology in place to monitor up to 75 per cent of US internet traffic, current and former security officials have revealed.
The security agency had previously claimed that only 0.00004 per cent of information on the internet is reviewed by analysts. However, it appears the security agency is able to monitor practically all online activity within the US, officials told the WSJ.
NSA programmes code-named Blarney, Fairview, Oakstar, Lithium and Stormbrew reportedly filter and gather information that passes through some of the most prominent US telecommunications companies including AT&T and Verizon.
Sources with knowledge of the inner workings of the programmes claim the NSA has been collecting the written content of emails sent between US citizens. The agency is also capable of filtering domestic phone calls made using VoIP services, it has been claimed.
These programs complement the NSA's Prism initiative which seeks to gather information from internet firms including Apple, Google, Facebook, Microsoft and Yahoo.
The surveillance net cast by the NSA is thought to include at least 12 of the biggest internet junctions within the US. It was previously believed that monitoring was restricted to undersea cables and foreign communications that entered the country.
The Journal cites specific examples of data collection. During the 2002 Winter Olympics in Salt Lake City, the FBI and NSA monitored the content of all email and text communications in the area for a period of around six months.
Currently, the NSA claims that it processes 29PB of data per day, but the true scale of collection may never be known. Questions have been raised about possible abuse of powers as it has been given broad powers and is essentially allowed to police itself.
An internal NSA audit from May 2012 uncovered 2,776 incidents of unauthorised collection, storage and distribution of legally protected communications over a 12-month period.
