The number of U.S. citizens and green card holders on the FBI's terror watch list has more than doubled since Christmas 2009, when the attempted bombing of an airliner over Detroit exposed flaws in the list and gaps in how government agencies used the information to screen potential security threats.
In a report released Friday, the Government Accountability Office said that watch list data collected from January 2009 through May 2011 showed that "more individuals have been denied boarding aircraft or subjected to additional physical screening before boarding" by the Transportation Security Administration. The report did not provide an exact figure for the increase.
A spokesman for the FBI's Terrorist Screening Center said that the total number of people on the no-fly list has doubled since the Christmas Day plot, to 20,000. But, he said, the number of U.S. citizens remains "very small" and relatively stable, at 500.
The FBI spokesman said there are about 550,000 people on the agency's larger terrorism watch list, approximately 98 percent of whom are foreign nationals.
The GAO said "hundreds more" foreign citizens were kept off flights after U.S. Customs and Border Protection "determined they would likely be deemed inadmissible upon arrival at a U.S. airport." In addition, the State Department revoked hundreds of visas shortly after Umar Farouk Abdulmutallab's botched attempt to ignite explosives in his underwear "because it determined that the individuals could present an immediate threat to the United States."
The Nigerian would-be bomber was on a British watch list at the time of the attempted attack. But despite warnings to U.S. officials from his father, Abdulmutallab was only on a general watch list in the U.S. and information about him was not considered specific enough to revoke his visa or place his name on a no-fly list.
The GAO report, a public version of a classified report issued late last year, credited TSA's Secure Flight program with reducing the likelihood of misidentifying passengers who are not on the list for those who are, as the late Sen. Edward Kennedy and other unlikely suspects were.