US Secretary of State John Kerry has said that while he does not know the particulars about allegations that the US bugged European Union offices, countries involved in international affairs undertake different activities to protect their national interests.
Kerry made the comments after Catherine Ashton, the EU foreign policy chief, raised the issue with him on Monday during a meeting on the sidelines of a security conference in Brunei.
"All I know is that that it is not unusual for lots of nations, but beyond that I'm not going to comment any further until I have all of the facts and find out precisely what the situation is," Kerry said.
The latest revelations from US intelligence whistleblower, Edward Snowden, published in a German magazine Der Spiegel showed that the National Security Agency lists 38 embassies and missions and describes them as "targets".
According to Der Spiegel, the NSA taps half a billion phone calls, emails and text messages in Germany in a typical month,much more than any other European peer.
The list includes the French, Italian and Greek embassies, as well as a other US allies including Japan.
Cold War-style behaviour
A German government spokesman said if media reports were true, it would be unacceptable Cold War-style behaviour between partners who require trust for a new trans-Atlantic trade area.
Also Chancellor Angela Merkel wanted to discuss the allegations with US President Barack Obama.
French President Francois Hollande also demanded the United States to immediately stop its alleged eavesdropping of the European Union.
The European Commission called in the US ambassador to the EU, William Kennard, for discussions on the issue with Pierre Vimont, the EU's top diplomat.
Al Jazeera's Jacky Rowland, reporting from Paris, said that if the allegations were proven to be true, they could risk the ongoing EU trade deal negotiations with the US and the trans-Atlantic alliance.
Der Spiegel quoted from a September 2010 "top secret" NSA document that it said Snowden had taken with him, and the magazine's journalists had seen in part.
The document outlines how the NSA spied on EU internal computer networks in Washington and at the United Nations, not only listening to conversations and phone calls, but also gaining access to documents and emails.
Surveillance methods included planting bugs into encrypted fax machines and other communications equipment.