Americans could learn more about the degree to which the secretive National Security Agency -- the government body charged with cracking codes and protecting critical information -- has been spying on U.S. citizens, if a suit filed on Friday by the Electronics Privacy Information Centre garners results. "The charter of the National Security Agency does not authorise domestic intelligence gathering," said Marc Rotenberg, director of EPIC, in a statement on Friday. "Yet we have reason to believe that the NSA is engaged in the indiscriminate acquisition and interception of domestic communications taking place all over the Internet." The questions arose from reports to the European Union last year that the United Kingdom and Australia, among other countries, had cooperated with the United States to collect electronic communications across national borders. In the report, the spy network was dubbed "Echelon." "We are concerned less with Echelon in particular and more with the NSA's eavesdropping practices in particular," said David Sobel, general counsel for EPIC. On Friday, EPIC filed a suit in federal court to free up documents regarding the legal justification for any surveillance that NSA had performed regarding U.S. citizens. These same documents were requested earlier this year by the House Intelligence Subcommittee, but the NSA refused to provide them. "There are a lot of interesting questions about the NSA's activity, and it raised a few eyebrows when they stonewalled the House subcommittee," said Sobel. In early June, EPIC filed a Freedom of Information Act request with the NSA, asking for the same documents requested by the House subcommittee, and the NSA replied that it would provide the documents by Oct. 30. The court filing comes after the NSA missed that deadline. The NSA has 30 days to respond to the court filing. They can see you... Read about how and why in Surveillance , a ZDNet News Special