Amid NSA spying revelations, tech leaders call for new restraints on agency Mounting revelations about the extent of NSA surveillance have alarmed technology leaders in recent days, driving a renewed push for significant legislative action from an industry that long tried to stay above the fray in Washington. After months of merely calling for the government to be more transparent about its surveillance requests, tech leaders have begun demanding substantive new restraints on how the National Security Agency collects and uses the vast quantities of information it scoops up around the globe, much of it from the data streams of U.S. companies. Graphic How the NSA is infiltrating private networks Related: Barton Gellman and Ashkan Soltani Agency positioned itself to collect from among millions of accounts, many belonging to Americans. Greg Miller Disclosure of surveillance program on allies results in both diplomatic and intelligence service predicaments. Timothy B. Lee Has NSA spying caused you to change how you use the Internet? Please let us know. The pivot marks an aggressive new posture for an industry that often has trod carefully in Washington - devoting more attention to blunting potentially damaging actions than to pushing initiatives that might prove controversial and alienate users from its lucrative services. Six leading technology companies - Facebook, Google, Apple, Yahoo, Microsoft and AOL - sent a letter to Senate leaders Thursday reflecting the sharpening industry strategy, praising the sponsors of a bill that would end the bulk collection of phone records of millions of Americans and create a privacy advocate to represent civil liberties interests within the secretive court that oversees the NSA. "Transparency is a critical first step to an informed public debate, but it is clear that more needs to be done," said the letter, which was sent to Sen. Patrick J. Leahy (D-Vt.), chairman of the Judiciary Committee and one of the bill's sponsors, as well as three other senators. Our companies believe that government surveillance practices should also be reformed to include substantial enhancements to privacy protections and appropriate oversight and accountability mechanisms for those programs. Although historically wary of Washington, the technology industry has been bulking up its political operations in the nation's capital for several years. It took a public stand against the Stop Online Piracy Act, commonly known as SOPA, with a massive Internet protest last year. More recently, tech leaders made a high-profile push in the immigration debate, calling for more visas for foreign-born workers. The tone of industry reaction to the NSA revelations has grown more aggressive since the first stories appeared in The Washington Post and Britain's Guardian newspaper in June. Companies that initially were focused on defending their reputations gradually began criticizing the government and challenging it in court. Some companies also have worked to harden their networks against infiltration. A turning point came with Thursday's Post revealing an NSA program that collects user information from Google and Yahoo as it moves among data centers overseas. To some, this amounted to a degree of intrusiveness that, though speculated about by privacy activists, was beyond what many in the industry thought possible. "Clearly, this is something new and different," said Joseph Lorenzo Hall, the chief technologist at the Center for Democracy and Technology, a Washington-based think tank that receives substantial industry support.