Bush told in August of specific threat to US

The "smoking gun" briefing received by President George Bush just a month before 11 September carried the heading, "Bin Laden determined to strike in the US", and focused on al-Qa'ida's ability to strike within the US mainland, it was revealed yesterday.

Despite White House claims that the briefing document related primarily to the threat of an attack on a US target overseas, the document also made very clear Mr bin Laden's desire "to bring the fight to America". It also emerged yesterday that the FBI had been aware for several years that al-Qa'ida was using US flying schools to train its pilots and, as early as 1996, it was told of a specific threat to use a plane in a suicide attack against the CIA's headquarters.

The latest revelations could prove very damaging to Mr Bush, who has insisted that, had he known al-Qa'ida was planning such an attack, he "would have done everything in [his] power to protect the American people". Earlier last week, Mr Bush's national security adviser, Condoleezza Rice, told reporters that the information given to the President was not specific.

For the past few days, Washington has been gripped by the revelation that the CIA passed a warning to Mr Bush on 6 August that talked of the possibility that al-Qa'ida might hijack a US airliner to use as a bargaining tool to release a jailed terrorist with links to the network.

Much of the information, it was said, was based on intelligence passed on by Britain and talked of hijacking only in the traditional sense – not raising the prospect that the hijackers might use the plane as a suicide weapon.

But yesterday the Washington Post revealed that the five-page CIA briefing actually dealt with the threat of an attack within the US. One source said that it made clear that Mr bin Laden and his followers wished to "bring the fight to America". Mr Bush had specifically requested the briefing because the intelligence he had received that summer related to the threat of an attack on US interests overseas.

Exactly what that briefing contained has become the focus of an growing political firestorm in Washington, with the Democrats seeking to inflict damage on the administration ahead of elections later this year. There is mounting pressure for an independent inquiry to be launched to investigate fully just what information was available about a possible al-Qa'ida attack. There have also been demands for the briefing document to be made public.

Meanwhile, the New York Times reported yesterday that the FBI had known for several years that the terror network was using American flight schools to train pilots.

In 1996, Abdul Hakim Murad, a Pakistani terrorist convicted of trying to destroy 12 American jumbo jets as they flew over the Pacific, intended to fly a plane into the CIA headquarters at Langley, Virginia. He had learnt to fly at several US flying schools, but the FBI discounted the threat of such suicide attacks.

Attention has also focused on a separate 1999 federal report that said al-Qa'ida could fly a plane into a key US target. The report, commissioned by the National Intelligence Council, an interagency group that oversees analysis, said: "Suicide bombers belonging to al-Qa'ida's martyrdom battalion could crash-land an aircraft packed with high explosives into the Pentagon ... the CIA or the White House."