AFP file photo of Angela Merkel
German spy chiefs will travel to the United States next week to demand explanations following allegations that US intelligence has been tapping Chancellor Angela Merkel's mobile phone.
"High-ranking government representatives will go rapidly to the United States in order to push forward discussions with the White House and the NSA on the allegations raised recently," said Georg Streiter, the chancellor's deputy spokesman, on Friday.
German media quoting sources close to the intelligence service reported on Saturday that the delegation will include top officials from the German secret service.
Revelations of US covert surveillance based on leaked documents from former US intelligence contractor Edward Snowden have sparked outrage in the European Union where privacy protection is a very sensitive issue.
The scandal widened this week on allegations that Merkel's phone was being tapped, prompting Berlin to summon the US ambassador - a highly unusual move between the close allies.
Merkel had called US President Barack Obama on Wednesday demanding answers and warning this would be "breach of trust" between international partners.
"Spying between friends, that's just not done," Merkel said, as she was heading into a EU summit earlier this week.