May 16-17, 2001: US Warned Bin Laden Supporters Are Inside US and Planning an Attack

On May 16, an anonymous person calls the US embassy in the United Arab Emirates and warns that bin Laden supporters have been in the US and are planning an attack in the US using “high explosives.” The caller mentions that operatives are infiltrating the US from Canada, but there is no mention of when or where the attack might occur. The next day, based on this warning, the first item on the agenda for counterterrorism “tsar” Richard Clarke’s interagency Counterterrorism Security Group (CSG) is entitled: “[Osama bin Laden]: Operation Planned in US.” The anonymous caller’s tip cannot be later corroborated. In July, the CIA will share the warning with the FBI, the INS, the US Customs Service, and the State Department. It will also be mentioned in the August 6, 2001 Presidential Daily Briefing given to President Bush (see August 6, 2001) and Bush will be told that the CIA and FBI are investigating it. But eventually, neither the CIA nor FBI is able to corraborate the information in the call. [US Congress, 9/18/2002; Washington Post, 9/19/2002; 9/11 Commission, 7/24/2004, pp. 255, 262, 535] There are some other possibly interlinked warnings this month also warning of an al-Qaeda plot to attack the US from Canada using explosives (see May 30, 2001, May 2001, and May 2001).