‘Explosive’ planes and bioweapons: CIA declassifies pre-9/11 intel warnings

Presidential briefings show US intelligence tracked potential attacks on American soil, aircraft hijackings and Bin Laden’s pursuit of unconventional weapons The CIA has declassified dozens of presidential intelligence briefings revealing that US officials were warned years before the September 11 attacks that Osama bin Laden and his Al-Qaeda network were considering strikes on American soil involving hijacked or explosive-packed aircraft, while also pursuing biological, chemical and nuclear weapons.

The agency released 71 President’s Daily Brief (PDB) products on Friday to mark the 25th anniversary of 9/11.

The collection, totaling more than 100 pages, is the largest release of CIA presidential intelligence related to the attacks and covers assessments dating from 1998 through the immediate aftermath of September 11, 2001.

Among the most striking documents is a September 1998 memorandum on Bin Laden’s intentions.

Intelligence indicated that his “preferred option” was to strike the US “on its own soil in Washington,” the CIA wrote, warning that his network “may fly an explosive-packed airplane into a US city.” To commemorate the 25th anniversary of 9/11, CIA released 71 President's Daily Briefs to give Americans a glimpse into our most sensitive intelligence from the years before and day after one of our Nation's darkest moments. https://t.co/Z2QIjcuvAj pic.twitter.com/N8ZoZ2OvtZ — CIA (@CIA) September 11, 2026 Three months later, another briefing warned that Bin Laden and his allies were preparing attacks in the US, including a plan to hijack an American airliner during the holiday season.

Read more How 9/11 turned a terrorist attack into a generation of war The newly released material also shows persistent concern about unconventional weapons.

A February 1998 assessment claimed Bin Laden and other extremists had sought to procure unspecified chemical, biological and nuclear substances.

By May 1999, the CIA assessed that Bin Laden was pursuing “a variety of options” for developing such weapons.

A subsequent June briefing said trainees at an Afghan camp had produced and tested “dozens of toxic chemicals and biological toxins,” and that operatives had experimented with adding radioactive material to explosives.

The best-known warning came on August 6, 2001, when President George W.

Bush received a briefing titled “Bin Ladin Determined To Strike in US.” It said Bin Laden had wanted to attack the US for years, cited suspicious activity consistent with preparations for hijackings, and noted that the FBI was conducting roughly 70 investigations into possible Al-Qaeda-linked activity in the country.