Fugitive American whistleblower Edward Snowden has leaked further details of alleged mass electronic surveillance by the US National Security Agency, suggesting many millions of text messages have been intercepted around the world daily.
The documents leaked by British news outlets reveal that the NSA scooped up about 200 million text or SMS messages a day at times in 2011, detailing everything from border crossings, financial transactions, location data and missed calls.
The Guardian newspaper reports that an NSA programme codenamed Dishfire collects pretty much anything it can from mobile phones outside the United States.
The NSA says that suggestions of arbitrary or unconstrained intelligence gathering are false, the BBC reports.
On Friday, President Barack Obama will set out changes to the operations of the NSA - reforms brought on by the revelations of Edward Snowden.
Civil liberties groups see this as a critically important turning point - the first time a president may curb the US intelligence services since the terror attacks on 11 September 2001.
Mr Snowden, a former contractor with the NSA, has been charged in the US with espionage and is currently a fugitive in Russia. His latest revelations adds to the impression of a vast and indiscriminate spying operation gleaning information about people who are not suspects.
The exposure of the NSA's programme has caused huge embarrassment to the US government - not least the suggestion it was spying on the mobile phone conversations of German Chancellor Angela Merkel.