As the attacks were taking place on September 11, 2001, NSA (National Security Agency) director Michael Hayden “ordered the counterterrorism unit to focus their attention on Middle Eastern intercepts and to translate and analyze them immediately as they were received, rather than starting with the oldest in the stack first, as was normally the case. It was then that analysts finally translated the two messages sent the day before, between pay phones in a highly dangerous area of Afghanistan and people in Saudi Arabia. To their shock, one said, ‘Tomorrow is zero hour,’ and the other said, ‘The match begins tomorrow.’ …The NSA would wait until the next day, September 12, before distributing the information to anyone else in Washington.”
– James Bamford, The Shadow Factory, Page 92