"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.
On Wednesday Süddeutsche Zeitung reported that new documents released by WikiLeaks show that the United States did not just tap German Chancellor Angela Merkel's phone but also eavesdropped on several ministers.
German-US relations were badly strained after fugitive US intelligence contractor Edward Snowden in 2013 revealed widespread US foreign surveillance, although a probe into the alleged tapping of Merkel's mobile phone was dropped last month over a lack of evidence.
But according to the latest revelations the US National Security Agency (NSA) did not limit its snooping activities to Merkel, and showed particular interest in the activities of the ministries of finance, economy and agriculture, Sueddeutsche Zeitung wrote.
It said whistleblowing website WikiLeaks had shown it a list of 69 phone numbers that were reportedly targeted, belonging to ministers and senior officials. The list appears to date back to between 2010 and 2012.
Current Economy Minister and Vice Chancellor Sigmar Gabriel was among those spied on by the NSA, the report said, although it noted that he was in the opposition at the time.
The list also features the number of former finance minister Oskar Lafontaine, who left the job in 1999. But the number is "still active", according to Sueddeutsche Zeitung, and now rings through to the secretariat of current Finance Minister Wolfgang Schäuble.
While Snowden alleged US spying on many European governments, his disclosures triggered particular anger in Germany where bitterness lingers over mass state spying on citizens by the Stasi secret police in former communist East Germany where Merkel grew up.
Merkel herself phoned US President Barack Obama over the revelations and in public told Germany's traditional post-war ally and NATO partner that "spying between friends just isn't on".
Washington appeared to confirm that her phone had been tapped when US officials said the cellphone was no longer a target.