BERLIN - German spy chiefs will travel to the United States next week to demand answers following allegations that US intelligence has been tapping Chancellor Angela Merkel's mobile phone, as a row over widespread US snooping threatened to hurt transatlantic ties.
Documents leaked by former US intelligence contractor Edward Snowden showing sweeping US surveillance on ordinary citizens' Internet searches and telephone records have already sparked outrage worldwide.
But the furore has intensified after allegations that world leaders including the presidents of Brazil and Mexico have been among spying targets.
This week, the scandal widened to Europe, with allegations that Merkel's phone was being tapped, prompting Berlin to summon the US ambassador - a highly unusual move between the close allies.
"High-ranking government representatives will go rapidly to the United States in order to push forward discussions with the White House and the NSA (National Security Agency) on the allegations raised recently," Georg Streiter, the chancellor's deputy spokesman, said Friday.
German media quoting sources close to the intelligence service reported Saturday that the delegation will include top officials from the German secret service.
Merkel telephoned US President Barack Obama on Wednesday saying that such spying would be a "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.
The spying row has prompted European leaders to demand a new deal with Washington on intelligence gathering that would maintain an essential alliance while keeping the fight against terrorism on track.
The 28 leaders also warn that while the bloc and the United States share a "close relationship", it must "be based on respect and trust".