The threats came in a blizzard around the anniversary of the Sept. 11 attacks — a series of videos from Al Qaeda's No. 2 warning of more strikes to come.

But U.S. intelligence agencies and many private security analysts doubt Al Qaeda or its elusive leader, Usama bin Laden, still maintain much if any operational control over far-flung terror cells.

They see no sign of a direct Al Qaeda hand in a flurry of recent attacks, such as the assault on the U.S. Embassy in Damascus, Syria, or the fatal shooting of a British tourist in Jordan. The French intelligence report that bin Laden may have died last month of typhoid merely highlights the uncertainty the West now has about any role he plays in the terror network.

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All that means those frightening videos may have been just that — designed to frighten the West and inspire followers — with little real punch behind them.

Bin Laden and his top deputy, Ayman al-Zawahri, are now "less like generals and more like talking heads, disseminating their violent ideology via satellite television in hopes of inspiring others to do their bidding," said Eben Kaplan of the Council on Foreign Relations think tank in New York.

Not everyone agrees. There are ominous signs in Afghanistan that Al Qaeda is trying to make an operational comeback as attacks, especially suicide missions, against U.S. and coalition forces increase.

Some experts also fear the absence of a major, Sept. 11-style attack simply means Al Qaeda is taking its time to plan a next spectacular strike.

Still, five years after the attack on the World Trade Center and the Pentagon, many analysts believe the day-to-day threat from Al Qaeda itself has dropped.

Paradoxically, however, the threat from Islamic extremists may have grown — and become broader, more diverse and more complex, and thus harder to combat.

"The absence of a formal, single organizational structure has contributed to making the fight against this brand of terrorism more elusive and difficult," the British think tank Chatham House said in a report this month as the videos were airing.

That view is also expressed in a classified U.S. intelligence report that says the Iraq war has increased the threat of terrorism by stirring up Islamic extremism around the globe. The report, which represented the consensus of 16 U.S. spy services, was completed in April and first reported in Sunday's New York Times and Washington Post.

After the U.S. and its allies ousted the Taliban in 2001, Al Qaeda apparently transformed itself into an ideological movement of self-sustaining cells that operate with little or no central direction, many analysts and intelligence officials believe. That makes them difficult to track — until they strike or make a mistake that leads the authorities to them.

It also makes it difficult to determine whether any specific attack was actually directed by Al Qaeda.

For example, British authorities insist there is no evidence Al Qaeda directed the July 2005 suicide attacks on the London transit system that killed 52 commuters.

Nonetheless, one of the four British Muslim bombers appeared later on a videotape made before his death, declaring his allegiance to bin Laden. That tape bore the logo of Al Qaeda's production company.

"Al Qaeda is crippled and is certainly not the organization it was. Al Qaeda, however, has placed extra emphasis on inspiring other groups and trying to mobilize other groups," the State Department's counterterrorism coordinator, Henry Crumpton, told the Council on Foreign Relations recently.

Al Qaeda's efforts to inspire appear to be focused on a worldwide wellspring of young, radicalized Muslims who share broad anger at the West, especially the United States.

But the goals, methods and targets of those far-flung radicals now vary widely. And not all extremist groups share Al Qaeda's vision of global struggle against the West, preferring in some cases to fight instead for specific national political aims.

Across the world, that means the threat is fractured into many parts — with the need to tailor defenses accordingly.

In Britain, mostly homegrown militants of Pakistani descent seem intent on staging the kind of big, spectacular attack that bin Laden used on Sept. 11.

Their efforts have focused again and again on jetliners — as during this summer's scare — and other big transportation systems such as subways.

Elsewhere, however, militants have diverged sharply from bin Laden. The assault this month on the U.S. Embassy in Damascus, Syria — which came just a day after al-Zawahri's warning tapes were aired — serves as a prime example.

In Syria, militants have focused on getting rid of President Bashar Assad and there is no sign they receive any operational direction from Al Qaeda.

In Iraq, the fight has mostly morphed into a sectarian conflict between Sunnis and Shiites for control of Iraq's future, although some foreign fighters inspired by Al Qaeda seem to still be involved.

Meanwhile, militants from Hamas and Hezbollah share the same hatred of the U.S. and Israel — but have sharply different ideologies and goals than Al Qaeda.

Hamas is focused on gaining power among the Palestinian community at the expense of its rival Fatah. Hezbollah wants to carve a role for itself as the leader of Shiite Muslims in Lebanon and the dominant political force in that country.

In places like Sudan and Somalia, Muslim militants are fighting for local power and control. They may have links to bin Laden from the past — but their only real connection seems to be when they invoke his name to resist the West.