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US security agency and UK GCHQ 'can spy on smartphones'

9 September 2013 Last updated at 06:10 BST

The US National Security Agency, the NSA, and Britain's spy agency, GCHQ, are reported to have cracked the security codes which protect data on all major smartphones.

The German news magazine, Der Spiegel, says it has seen secret documents suggesting this is part of a joint effort to gather intelligence on potential threats.

Stephan Evans reports from Berlin.