Original Report Follows:
The U.S. National Security Agency's website, nsa.gov, was knocked offline Friday afternoon, and as of Friday evening, it was still unavailable. Only a browser message indicating that the server was not responding appeared.
Sources quoted by various news agencies have speculated that the site has apparently fallen victim to a DDoS (distributed denial-of-service) attack, and that it was believed that the hacker group Anonymous would claim responsibility. However, as of the time of publication of this report, the group has not claimed responsibility.