The US' National Security Agency has reportedly defended its practice of allegedly tracking millions of foreign cellphones overseas everyday and said that it is legal under a US presidential order governing the programme.
The NSA said that it isn't tracking every foreign phone and call, and that it takes measures to limit how much US data is collected.
According to Fox News, spokeswoman Vanee Vines said that the practice is legal under the order governing US espionage, known as Executive Order 12333 and said that NSA analysts must treat any US citizens' data they accidentally gather differently.
The secret documents revealed by NSA whistleblower Edward Snowden indicated that the US spy agency has been gathering nearly five billion records a day on the whereabouts of cell phones globally.
The move enabled the agency to track the movements of individuals and map their relationships in ways that would have been previously unimaginable.