Disagreement over timing of arrests

NBC News has learned that U.S. and British authorities had a significant disagreement over when to move in on the suspects in the alleged plot to bring down trans-Atlantic airliners bound for the United States.

Best part: In contrast to previous reports, the official suggested an attack was not imminent, saying the suspects had not yet purchased any airline tickets. In fact, some did not even have passports.

Emphasis mine.