A picture of the head of the al-Qaeda terror network, Osama bin1 Laden2. The United States faces growing threats on multiple fronts with Al-Qaeda still the top danger, but Iran on the rise and on course to produce nuclear weapons early in the next decade, US intelligence chiefs said Tuesday. [AFP]

Osama bin Laden, if he's alive, celebrated³ his 50th birthday on Saturday, and his friends in the Taliban prayed for his long life.

The al Qaeda leader's long silence since the September 11, 2001 attacks has fuelled speculation⁴ that the world's most-wanted fugitive⁵ may have died, though many in the international intelligence community reckon Islamist militant⁶ Web sites would circulate word of his death.

"He is alive. I am 100 percent sure," Taliban spokesman Mullah Hayatullah Khan told reporters, adding that senior leaders were in touch with bin Laden.

Khan said special prayers were offered by Taliban fighters in camps in Afghanistan to mark bin Laden's birth on March 10, 1957, in the Saudi Arabian city of Jeddah.

"We prayed that Allah may give him 200 years to live," Khan said.

"And we offered collective and long prayers for him because he is a great mujahid (holy warrior)."

The most recent videotape of bin Laden was released in late 2004.

But a long silence since then has fuelled rumours⁷ that bin Laden is unwell, or dead, though the United States fears that the al Qaeda network he founded is rebuilding its base in Pakistani tribal⁸ lands, and has forged ties with affiliates⁹ in Europe, North Africa and the Middle East.

Dead or alive, bin Laden is revered¹⁰ by some as the symbolic¹¹ leader of a global jihad, or holy war, against the United States, following the September 11, 2001 attacks on New York and Washington that killed more than 3,000 people.