Revelations about a far-reaching intelligence program in the United States leaked last week aren't just causing problems for President Barack Obama at home. While American citizens are left wondering whether their privacy has been violated by the Internet and phone surveillance, officials abroad are expressing serious concerns too.

Germany, which has particularly strict data privacy laws, is reportedly one of the most heavily monitored countries in the surveillance program, and Justice Minister Sabine Leutheusser-Schnarrenberger demanded an explanation on Tuesday. "The suspicion of excessive surveillance of communication is so alarming that it cannot be ignored," she wrote  in an editorial for SPIEGEL ONLINE. "For that reason, openness and clarification by the US administration itself should be paramount at this point. All facts must be put on the table."

Merkel To Address Issue with Obama

The day before, Chancellor Angela Merkel's spokesman Steffen Seibert said the German leader would discuss the matter with President Obama when he makes his first state visit to Berlin as president later this month. Obama has defended the spying program as a "modest encroachment" on privacy .

German Consumer Protection Minister Ilse Aigner has also called for "clear answers" from the companies implicated in the government document leak, and the Green Party demanded an immediate investigation by the German government.

"Total surveillance of all German citizens by the NSA is completely disproportionate," Volker Beck, secretary of the Green Party group in parliament, said on Monday.

Strong Reaction from Europe

European politicians are also worried about the surveillance, which the European Parliament planned to debate on Tuesday. Officials in Brussels reportedly plan to discuss the matter with US diplomats at a trans-Atlantic  ministerial meeting later this week in Dublin.

"It would be unacceptable and would need swift action from the EU if indeed the US National Security Agency were processing European data without permission," Guy Verhofstadt, a Belgian member of the European Parliament and a leader in the Alde group of liberal parties, told the Associated Press on Tuesday.

At issue is a large-scale, top-secret program, codenamed Prism, undertaken by the National Security Agency (NSA), an American foreign intelligence agency. It tracks suspicious messages from outside the United States that are transmitted through American providers such as Google, Yahoo, Facebook and Skype, including emails, phone numbers, videos, photos and other forms of online communication.

Details of the program were leaked by Edward Snowden , a 29-year-old former CIA employee who worked as a contractor for Booz Allen Hamilton at the NSA. There he had access to the documents about the counterterrorism surveillance, which he gave to the Guardian and Washington Post before going into hiding in Hong Kong, where he revealed his identity on Sunday. US authorities are now reviewing whether Snowden can be prosecuted for what some politicians there have called a treasonous act.

The scandal has revealed state surveillance of a previously unimaginable scope by the US both at home and abroad, the latter of which is of particular concern to German commentators on Tuesday.

Center-left daily Süddeutsche Zeitung writes:

"It may be that US citizens can defend themselves under the US Constitution. But that doesn't apply to foreigners. Facebook users in Germany have as little protection from the US Constitution as those in Afghanistan. Germany is the country in Europe whose telephone and Internet  communications are being spied on the most intensely by the US. ... But even the best rulings from Germany's high court are useless because the majority of the Internet's architecture is located in the US. As a consequence, US authorities have the power of access, and this is stronger than basic German rights."

"The NSA case shows the expansiveness of preventive security state logic. Those who want to prevent crimes and terrorism -- whatever the cost -- can never know enough, and will always try to find out more in the name of security. Under the reign of terrorism, the legal system is changing. To track down the 'bad guys,' the entire population is being spied on with sophisticated methods in which intelligence agencies, police and possibly private networks are all cooperating. The US is a pioneer in introducing an infrastructure of surveillance."

"The only good thing about the NSA spying is that it exposes the principle tenet of domestic security that has been used to justify the rebuilding of the security system since Sept. 11, 2001: That those with nothing to hide have nothing to fear. This is simply a stupid idea."

Left-leaning Berliner Zeitung writes:

"The chancellor's spokesman Steffen Seibert has now officially announced that Merkel will question Obama when he visits about the apparent systematic spying, particularly of German Internet users, by US intelligence. This is the least that citizens should expect. But more than that, the issue here is the protection of the federal government from total surveillance by a foreign state, no matter how friendly it may be."

"Germany has strict privacy laws -- even if many people now flaunt their data in a practically exhibitionist fashion on social networks. But that is their choice, after all. The federal government must explain what they intend to do about the immoderate and unwarranted clandestine surveillance of its citizens by American intelligence agencies. And whether the German services know about and possibly use this illegally acquired knowledge."

Left-leaning Die Tageszeitung writes:

"Basic civil rights around the world, which are taken for granted far too naively in Western democracies, are being placed under attack by state 'security architecture' such as the US spying program Prism. In Germany -- where the relatively recent examples of two totalitarian state systems mean that the consequences of state monitoring in the private sector are still in living memory -- three things must result from this: clarification of the situation, defense and self-protection."

"It is right that the opposition has called for a radical review by the governmnent. But it is already foreseeable that the questions about what German intelligence knew will be rejected under the usual pretexts. The most popular argument is that the government best decides alone what kind of surveillance doesn't harm the public. Obama  makes a similar argument about the need for monitoring measures by his intelligence agencies. But the German government shouldn't make the same argument. It may sound utopian, but it would be appropriate to offer fugitive whistleblower Edward Snowden political asylum in Germany."

Conservative daily Frankfurter Allgemeine Zeitung writes:

"Whether it's with Facebook, Google, Yahoo or Microsoft -- user confidence has been shaken. According to statements made by the source of the revelations, Snowden, all users should be asking whether they themselves, and especially their personal data, are in good hands with these companies."

"For years, German Internet providers have complained among themselves about the tough data protection laws to which they are subject in the European Union. At the same time, they looked enviously at their American counterparts, who are obviously subject to very flexible data protection rules. But these days could be over now. European providers should take advantage of their data protection requirements as a unique selling point."