Der Spiegel said Merkel’s mobile telephone had been listed by the NSA’s Special Collection Service (SCS) since 2002 – marked as “GE Chancellor Merkel” – and was still on the list weeks before Obama visited Berlin in June.

In an SCS document cited by the magazine, the agency said it had a “not legally registered spying branch” in the U.S. embassy in Berlin, the exposure of which would lead to “grave damage for the relations of the United States to another government”.

From there, NSA and CIA staff were tapping communication in the Berlin’s government district with high-tech surveillance.

Quoting a secret document from 2010, Der Spiegel said such branches existed in about 80 locations around the world, including Paris, Madrid, Rome, Prague, Geneva and Frankfurt.