U.S. intelligence agencies have a direct tap into the central servers of top U.S. Internet companies, letting agents trawl for suspicious activity, sources have confirmed to NBC News. The highly classified program, which is called PRISM and run by the National Security Agency and the FBI, was first reported Thursday evening by The Washington Post — which reported that it had obtained an internal NSA presentation on the program — and by The Guardian. According to NBC News' sources, PRISM lets agents cull audio, video, photos, emails, documents and connection logs in order to track Internet users' contacts. It was designed, they said, to look at international communications, but they disputed the Post's report that the program engaged in "data mining," saying it instead engaged in "data collection." Companies contacted by NBC News — including digital giants like Google, Facebook, Apple, Microsoft and Yahoo — denied knowledge of the program; however, the presentation obtained by the Post described the program as a "partnership" with tech companies.