Reports that the US National Security Agency is spying on European allies and bugging embassies have been met with strong condemnation in Germany, where chancellor Angela Merkel angrily denounced the agency's activities earlier this month as "unacceptable." But new documents obtained by Der Spiegel reportedly show that German intelligence services actually make significant use of a powerful NSA spying program used to monitor internet communications.

According to Der Spiegel, Germany's Federal Intelligence Service (BND) and Federal Office for the Protection of the Constitution (BFV) — which deal in foreign and domestic intelligence, respectively — have been actively using an NSA program called XKEYSCORE, which was revealed earlier this month in a series of top secret Powerpoint slides published in the Brazilian newspaper O Globo. The program involves the mass-collection of internet metadata or "digital network intelligence" such as IP addresses and terms typed into search engines. The tool allows analysts to review such information retroactively both on specific targets and in "full-take," capturing days worth of raw data including, in some cases, the contents of communications. The documents reportedly say that the program intends to let German agencies "expand their ability to support NSA as we jointly prosecute CT (counterterrorism) targets."

The NSA's spying programs have struck a nerve in German citizens, many of whom still hold memories of the East German Stasi, the infamous secret police force that spied on countless innocent civilians before the fall of the Berlin Wall. But Der Spiegel says the new documents reveal that the German government has been a proactive partner in the mass-surveillance efforts, citing "willingness to take risks and to pursue new opportunities for cooperation with the US," and noting the "eagerness and desire" of Gerhardt Schindler, the head of Germany's Federal Intelligence Service.