"The document suggests that in addition to installing bugs in the building in downtown Washington, DC, the European Union representation's computer network was also infiltrated. In this way, the Americans were able to access discussions in EU rooms as well as emails and internal documents on computers," claims the news outlet.
It also suggest that the NSA has been spying in a similar way on the EU representation to the United Nations, as well as EU officers in the Justus Lipsius Building in Brussels, the home of the EU Council of Ministers and the European Council.
These revelations have been backed up a day later by Guardian's journalists, who disclosed that 38 embassies and missions have been targeted.
"Along with traditional ideological adversaries and sensitive Middle Eastern countries, the list of targets includes the EU missions and the French, Italian and Greek embassies, as well as a number of other American allies, including Japan, Mexico, South Korea, India and Turkey. The list in the September 2010 document does not mention the UK, Germany or other western European states," they wrote.
"The documents suggest the aim of the bugging exercise against the EU embassy in central Washington is to gather inside knowledge of policy disagreements on global issues and other rifts between member states." So, it was definitely not performed to foil terrorist plots.
The EU and some of its member states reacted to the revelations by throwing around words like "shocked", "worried", "unacceptable", and EU Justice Commissioner Viviane Reding stated that they "cannot negotiate over a big trans-Atlantic market if there is the slightest doubt that our partners are carrying out spying activities on the offices of our negotiators. The American authorities should eliminate any such doubt swiftly."
The Germanyís Federal Prosecutorís office is apparently thinking about bringing charges against the UK and US intelligence services.
In the meantime, the US is sticking to the "everybody else is doing it, nothing to see here" official defense.
On Sunday, Der Spiegel continued with revelations about NSA spying, saying that it the NSA monitors around half a billion telephone calls, emails and text messages in Germany every month.
"One top secret document also states that while Germany may be a partner, it is still also a target of the NSA's electronic snooping," they wrote. "According to the document, Germany is a so-called '3rd party foreign partner.' The only countries that are explicitly excluded from spying attacks are Australia, Canada, New Zealand and the UK."
The revelations are bound to affect the upcoming trade talks between the US and the European Union.
On the US front, A group of 26 senators are asking James Clapper, the Director of National Intelligence, to disclose information on whether the NSA did collect data on U.S. citizens' financial information and credit card purchases.
Also during the weekend, The Washington Post published four more slides from the secret presentation on the PRISM surveillance program, putting into a larger context and implying real-time surveillance capabilities.
Reading our newsletter every Monday will keep you up-to-date with security news.
Receive a daily digest of the latest security news.