A German magazine says the U.S. National Security Agency kept a dossier with more than 300 entries on German Chancellor Angela Merkel, a revelation that could further strain relations between the two countries over the scope of U.S. surveillance programs.
Der Spiegel magazine says the secret file was part of a database about foreign heads of state that also included the heads of Peru, Somalia, Belarus and other countries.
The magazine did not specify what was in the secret reports.
Der Spiegel said Saturday the information is in documents leaked by former U.S. national security contractor Edward Snowden. The NSA says he stole 1.7 million documents before fleeing to asylum in Russia.
Der Spiegel also says a British intelligence service infiltrated Germany Internet companies.
At an October summit in Brussels, Chancellor Merkel said she made it clear to Mr. Obama that spying on allies was unacceptable. She commented after allegations emerged that the NSA had monitored her cell phone calls.
In January, Mr. Obama outlined a series of changes to U.S. surveillance operations, including a plan that would virtually end spying on foreign allies.