CIA releases declassified presidential briefs showing pre-9/11 warnings of airplane attack

Newly declassified documents show that three years before 9/11, US intelligence officials were discussing the possibility that al-Qaeda "may fly an explosive airplane into a US city".

On Friday, the 25th anniversary of hijacked planes being crashed into the World Trade Center, Pentagon and a Pennsylvania field, the CIA released 71 daily presidential briefs spanning from early 1998 to the day after the attacks.

Another document, dated 12 September 2001, said the plot's existence was "widely known" in extremist circles.

President's Daily Briefs are among the most secretive intelligence analyses in the US government, and typically remain classified for 40 or 50 years after publication.

"Twenty-five years ago, the 9/11 attacks struck a blow to our nation, but they did not break us," CIA Director John Ratlcliffe said in a statement

"Generations of C.I.A. officers have since dedicated their careers to securing justice for our fallen Americans and ensuring Al Qaeda would never again harm our country," he added.

Of the 71 documents published by the CIA, 69 have never been seen by the public.

The briefs - many still heavily redacted - were created during both the Clinton and Bush administrations.

They show increasing alarm over the al-Qaeda network and its leader, Osama Bin Laden. They also echo the assessment of the official commission that reviewed what happened that day that US intelligence repeatedly warned of a potential attack, but had few details or sense of the scale of what was coming.

One briefing document, dated 10 September 1998, reported Bin Laden's preferred location for a strike was within the US, with Washington a prime target.

The group, a CIA analyst wrote, "may fly an explosive-packed airplane into a US city".

While the 9/11 Commission's 2004 report noted US intelligence believed al-Qaeda was considering using an airplane in the attack, it was never clear that the warning reached then-President Bill Clinton.

Bin Laden and al-Qaeda were already well-known to the US intelligence community in1998.

In August that year, they attacked US embassies in both Kenya and Tanzania, killing 224 people and prompting the US to strike targets in Afghanistan and Sudan with cruise missiles.

One document written on 28 August 1998 - 21 days after the embassy attacks and eight days after the US retaliation - warned that the network remained intact and that Bin Laden was actively "considering attacks in the US".

Only one of the presidential briefings in the release comes from after the attacks. It was sent to the White House 0400 on 12 September, just under 20 hours from when the first aircraft struck the World Trade Center in New York.

The report noted that "mounting evidence" suggested extremists in Afghanistan and the Persian Gulf "were aware" the attack had been imminent.

Another partially redacted sentence said the plot was "widely known" among extremists and that Bin Laden may have relocated to Kabul, in Afghanistan, to avoid conflict with the country's Taliban rulers with whom he had "clashed" over the plan.

The then-head of the Taliban, Mullah Omar, was reported to have been evacuated with his family from the southern Afghan city of Kandahar immediately following the attacks. Less than a month later, the US and its allies invaded Afghanistan, seeking to destroy al-Qaeda.