The US National Security Agency was allowed to collect email and internet usage records of citizens for more than 10 years, secret documents have revealed.
The bulk collection of these records was allowed under a programme begun in 2001 and halted only in 2011 for operational and resource reasons by the Obama administration, according to the Guardian.
Documents obtained by the paper indicate that, under the programme, a federal judge sitting on a secret surveillance panel would approve the bulk collection order for internet metadata every 90 days
The revelation comes just weeks after it was revealed the NSA was collecting the phone records of millions of US citizens and monitoring internet communications under the Prism programme.
The bulk collection of internet data was started under the Bush administration's wide ranging warrantless surveillance programme known as Sellar Wind.
The internet metadata detailed the accounts to which US citizens sent emails and from which they received emails.
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The metadata included the internet protocol addresses (IP) used by people inside the US when sending emails, which could reflect their physical location.
Although the programme was officially ended in 2011 after more than two years into the Obama administration, some collection of US communications continues, according to the Guardian.
In December 2012, for example, the NSA launched a new programme, allowing it to analyse communications with one end inside the US.
However, the Obama administration argues that its internal checks on NSA surveillance programmes ensure the protection of citizens’ privacy.