The United States has been spying on German Chancellor Angela Merkel’s mobile phone for more than a decade, Deutsche Welle reports, citing the German Der Spiegel magazine.

On Saturday, the magazine reported that the National Security Agency (NSA) had listed Merkel’s mobile telephone since 2002, beginning under the Bush administration, and that it had remained on the list weeks before current President Barack Obama visited Berlin in June.

The German magazine also reported that NSA and CIA staff had tapped government communications with high-tech surveillance from the U.S. Embassy in Berlin.

Der Spiegel cited an NSA document saying the agency had a “not legally registered spying branch” in the Berlin embassy, the exposure of which would lead to “grave damage for the relations of the United States to another government.”

Quoting a secret 2010 document, the magazine reported that such branches existed in about 80 locations worldwide, including Paris, Madrid, Rome, Prague, Geneva and Frankfurt.

The magazine reported that it remained unclear whether the NSA had recorded conversations or just connection data.

Merkel telephoned Obama on Wednesday, after reports surfaced that she had been spied upon, saying that such spying would be a “breach of trust” between international partners.

Obama apologized to Merkel when she called Wednesday to seek clarification, according to Der Spiegel.

The Germany newspaper Frankfurter Allgemeine Sonntagszeitung reported that Obama told Merkel he had not known of the bugging. Merkel’s spokesman and the White House declined to speak on the issue.

Responding to the reports of the monitoring of Merkel’s calls, White House spokesperson Jay Carney said that “The United States is not monitoring and will not monitor the communications of the chancellor.”

The French Le Monde newspaper reported this week thatthe NSA collected more than 70 million recordings of French citizens’ telephone data – a claim contested by the top U.S. intelligence chief.

The Guardian reported on Thursday, also based on a classified document provided by Snowden, that the (NSA) monitored the phone conversations of 35 world leaders after being given the numbers by an official in another U.S. government department.