Reuters reports today that US intelligence agencies may have bugged Angela Merkel's phone for more than 10 years.  Germany is sending intelligence chiefs to Washington to discuss the matter.

BERLIN (Reuters) - The United States may have bugged Angela Merkel's phone for more than 10 years, according to a news report on Saturday that also said President Barack Obama told the German leader he would have stopped it happening had he known about it.

Germany's outrage over reports of bugging of Merkel's phone by the U.S. National Security Agency (NSA) prompted it to summon the U.S. ambassador this week for the first time in living memory, an unprecedented post-war diplomatic rift.

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.