Moreover the European Union said on Sunday said it has questioned US authorities about alleged US spying on EU offices and was waiting for Washington's response.
“We have immediately been in contact with the US authorities in Washington DC and in Brussels and have confronted them with the press reports, “ the European Commission said in a statement.
“They have told us they are checking on the accuracy of the information released yesterday and will come back to us,” it said referring to a report on the spying claims by German weekly Der Spiegel.
The revelations of alleged US surveillance programmes based on documents taken by fugitive former National Security Agency contractor Edward Snowden have raised a political furore in the United States and abroad over the balance between privacy rights and national security.
Exposing the latest details in a string of reputed spying programmes, Der Spiegel quoted from an internal NSA document which it said its reporters had seen.
It said the document showed that the NSA monitored phone calls, text messages, emails and internet chat contributions and has saved the metadata, that is the connections and not the content, at its headquarters.
On an average day, the NSA monitored about 20 million German phone connections and 10 million internet data sets, rising to 60 million phone connections on busy days, the report said.
A Spiegel report on Saturday that the NSA had spied on European Union offices caused outrage among EU policymakers, with some even calling for a suspension to talks for a free trade agreement between Washington and the EU.
In France, Der Spiegel reported, the United States taps about 2 million connection data a day.