Terror mastermind Osama bin Laden is cut-off from the day-to-day operations of al-Qaeda and is concentrating his energies on survival, according to the CIA.

But the terrorist organisation continues to spreading its influence in Africa and the Middle East and remains the single greatest threat to US security.

CIA director Michael Hayden said: "Al-Qaeda operating from its safe haven in Pakistan's tribal areas remains the most clear and present danger to the safety of the United States.

"If there is a major strike against this country, it will bear the fingerprints of al-Qaeda."

"Even today, al-Qaeda in Iraq remains that organisation's largest regional affiliate. It still can and does inflict damage.

"No matter what residual tactical strength it retains in Iraq though, the most important point that al-Qaeda in Iraq is on the verge of strategic defeat."

Mr Hayden said bin Laden, hiding in the lawless tribal border area of Pakistan, "appears to be largely isolated from the day-to-day operations of the organisation he nominally heads."

But he added: "I can assure you, although there has been press speculation to the contrary, that the hunt for bin Laden is very much at the top of CIA's priority list.

"Because of his iconic stature, his death or capture clearly would have a significant impact on the confidence of his followers, both core al-Qaeda and these unaffiliated extremists, unaffiliated extremists throughout the world."

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