Documents leaked by former US National Security Agency contractor Edward Snowden show that Britain's surveillance agency is operating a network of "electronic spy posts" from within a stone's throw of the Bundestag and German chancellor's office, the Independent reported.

NSA documents, in conjunction with aerial photographs and information about past spying activities in Germany, suggest that Britain is operating its own covert listening station close to the German parliament, and Chancellor Angela Merkel's offices in the Chancellery, using hi-tech equipment housed on the embassy roof, the British newspaper reported.

The spying operation, conducted by GCHQ at diplomatic buildings around the world to intercept data in host nations, is being carried out together with the United States and other key partners, the Independent reported.

Spy agencies across Western Europe are working together on mass surveillance of internet and phone traffic comparable to programmes run by their US counterpart and denounced by European governments, Britain's Guardian newspaper reported on Saturday.

There has been particular anger in Germany, a close ally of the United States, over allegations that the NSA monitored Merkel's mobile phone.

GCHQ could not be immediately reached when contacted by Reuters. - Reuters