Chancellor Angela Merkel's office Thursday asked the US ambassador to discuss new allegations about NSA spying, a German government source said.

"We confirm that US ambassador (John) Emerson was invited to the chancellery to talk," the German government source told AFP, after the Frankfurter Allgemeine daily said Merkel's chief of staff Peter Altmaier had asked for the meeting.

German media had reported Wednesday that new documents released by WikiLeaks appear to show the United States did not just tap Merkel's mobile phone but also eavesdropped on several ministers.