The CIA declassified 71 President's Daily Briefs on the 25th anniversary of 9/11, revealing repeated warnings about Osama bin Laden and al-Qaeda from 1998 to 2001.
A September 10, 1998 briefing warned that bin Laden preferred attacks inside the United States and noted assessments that al-Qaeda might fly an explosive-packed airplane into a U.S. city.
Following the September 11 attacks, a subsequent briefing delivered to the White House indicated that extremists in Afghanistan and the Persian Gulf had prior knowledge of the imminent operation.