The head of the CIA has warned that the al-Qaeda terror network remains capable of mounting another 9/11-style attack on America.
Tenet said al-Qaeda should not be underestimated
George Tenet said although the network had been seriously damaged, it continued to pose a major threat to the United States and its allies.
Mr Tenet said there was evidence al-Qaeda was planning to recruit airline pilots to carry out attacks.
"Terrorists" were still trying to obtain "catastrophic weapons," he said.
Earlier, Arabic television broadcast an audiotape allegedly recorded by a top al-Qaeda leader, in which he accused US President George W Bush of exaggerating his successes in the "war on terror".
Addressing the US Senate Intelligence Committee, Mr Tenet said the intelligence service had uncovered "chilling plots" to attack Americans.
"Even catastrophic attacks on the scale of 11 September  remain
within al-Qaeda's reach," he said.
"Make no mistake: these plots are hatched abroad, but they target US soil and that of our allies."
He said al-Qaeda was trying to evade tightened security in Europe, the Middle East and South-East Asia, and continue to target airliners.
"On aircraft plots alone, we have uncovered new plans to recruit pilots," he said.
The CIA chief said while al-Qaeda's leadership had been seriously damaged, other "terrorist" groups were inspired by its ideology.
"The steady growth of [al-Qaeda leader] Osama Bin Laden's anti-US sentiment through the wider Sunni [Islamic] extremist movement, and the broad dissemination of al-Qaeda's destructive expertise, ensure that a serious threat will remain for the foreseeable future - with or without al-Qaeda in the picture," said Mr Tenet.
He said the United States continued to pursue Bin Laden, who he said had "gone deep underground".
"We are hunting him in some of the most unfriendly regions on Earth. We follow every lead."