America's largest spy agency has been globally collecting around 200 million text messages a-day, according to new files leaked by National Security Agency whistleblower Edward Snowden.
A joint investigation of the files by the UK's Guardian newspaper and Channel 4 News alleges that information collected by the NSA's "Dishfire" program included locations, contact networks, and credit card details.
The files have raised concerns that the UK's communications headquarters GCHQ has broken Britain's privacy laws as it appears to have used the database to search the metadata of UK citizens.
GCHQ is not legally allowed to search message contents without a warrant, however the NSA appears to be unrestrained by such laws.
The files reveal that GCHQ asked its analysts to search under 'events' data which would prevent agents from seeing the content of the messages.
A GCHQ memo revealed by the investigation outlined the usefulness of the Dishfire program,
"In contrast to GCHQ equivalents, DISHFIRE contains a large volume of unselected SMS traffic," it said. "This makes it particularly useful for the development of new targets, since it is possible to examine the content of messages sent months or even years before the target was known to be of interest."
The NSA automatically removes all SMS information held on Americans, but there are no such restrictions on foreign citizens' details.
United States President Barack Obama on Friday called for an overhaul of the NSA's Phone Data Collection Program