"This cannot be justified from any point of view by the fight against international terrorism or by averting danger," Bosbach said.
In the past, much of the official outrage in Europe about revelations of U.S. communications intercepts leaked by former NSA contract worker Edward Snowden seemed designed for internal political consumption in countries that readily acknowledge conducting major spying operations themselves. But there has been a new discernible vein of anger in Europe as the scale of the NSA's reported operations became known, as well as the possible targeting of a prominent leader like Merkel, presumably for inside political or economic information.
"Nobody in Germany will be able to say any longer that NSA surveillance—which is apparently happening worldwide and millions of times—is serving solely intelligence-gathering or defense against Islamic terror or weapons proliferation," said Hans-Christian Strobele, a member of the German parliamentary oversight committee.
"Because, if you tap the cellphone or the phone connection of the presidents of France or Brazil, or the cellphone of the chancellor, then this is no longer about collecting intelligence about international terrorism, but then that is about competition, about getting advantages in this competition and winning. That's why today is a watershed moment."
European Union Commission President Jose Manuel Borroso said for many Europeans, eavesdropping on their phone calls or reading their emails is particularly objectionable because it raises the specter of totalitarian regimes of the recent past.
"At least in Europe, we consider the right to privacy a fundamental right and it is a very serious matter. We cannot, let's say, pretend it is just something accessory," Barroso told a presummit news conference.
Referring to the East German Communist secret police, the feared Stasi, Barroso said, "to speak about Chancellor Merkel, in Germany there was a part of Germany where there was a political police that was spying on people's lives every day. So we know very recently what totalitarianism means. And we know very well what comes, what happens when the state uses powers that intrude in people's lives. So it is a very important issue, not only for Germany but for Europe in general."
In Berlin, the German Foreign Ministry summoned the U.S. ambassador to stress how seriously it takes the reported spying on Merkel. Germany's defense minister said his country and Europe can't return "to business as usual" with Washington, given the number of reports that the United States has eavesdropped on allied nations.
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"The Americans are and remain our best friends, but this is absolutely not right," Thomas de Maiziere, who served as Merkel's chief of staff, told ARD television. "I have reckoned for years with my cellphone being monitored, but I wasn't reckoning with the Americans."
A German parliamentary committee that oversees the country's intelligence service met to discuss the spying allegations. Its head, Thomas Oppermann, recalled previous reports to the panel that U.S. authorities had denied violating German interests, and said, "we were apparently deceived by the American side."
—By the Associated Press