U.S. intelligence agencies may have spied on German Chancellor Angela Merkel's mobile phone, which would be a "grave breach of trust," the German government said late Wednesday.
The German government has asked for "immediate and comprehensive" information on the possible surveillance, Merkel spokesman Steffen Seibert said in a statement posted on the German government's website.
Seibert didn't disclose how the German government received information about the surveillance. Merkel, in a phone call with U.S. President Barack Obama, said such surveillance would be "completely unacceptable," the statement said.
Merkel told Obama she expects U.S. authorities to detail the scope of monitoring practices in Germany, Seibert said.
Obama assured Merkel that intelligence agencies, including the U.S. National Security Agency, are not monitoring Merkel's phone, according to news reports.
The German allegations follow months of news reports on the National Security Agency's surveillance programs. This week, German news magazine Der Spiegel reported that the NSA hacked into an email server used by former Mexico President Felipe Calderon in 2010.