The United States Central Intelligence Agency (CIA) has released previously classified intelligence briefs from the period surrounding the September 11, 2001 terrorist attacks, shedding further light on security concerns and warnings that preceded the attacks.
The documents, described as 9/11-era briefs, include warnings about the possibility of an aircraft-related attack and provide additional insight into the intelligence environment before the attacks on the United States.
The release offers historical context on the information available to American intelligence agencies during the period leading up to September 11, when al-Qaeda was already regarded as a significant terrorist threat.
The September 11 attacks involved the hijacking of four commercial aircraft by members of al-Qaeda. Two aircraft were flown into the World Trade Center towers in New York, while another struck the Pentagon in Virginia. A fourth aircraft crashed in Pennsylvania after passengers attempted to regain control of the plane.
The attacks killed nearly 3,000 people and triggered major changes in US national security and counterterrorism policy.
The newly released material is expected to provide researchers and the public with further information about intelligence assessments and warnings from that period, particularly regarding the potential use of aircraft in a terrorist attack.
The documents also contribute to the continuing examination of what US intelligence agencies knew before the attacks, how threats were assessed and how information was communicated within the national security system.
The release comes more than two decades after the attacks and forms part of the continuing declassification of historical intelligence material relating to one of the most consequential terrorist attacks in modern history.
The CIA’s publication of the briefs provides additional primary-source material for researchers examining the intelligence failures, warnings and security challenges that preceded September 11.
