Where's Osama? And how much should we care?

The Uighur region of Northwestern China. An island in the Indonesian archipelago. The arid and mountainous border between Yemen and Saudi Arabia. Pakistan's North West Frontier Province.

Ask intelligence experts where they think Osama bin Laden might be hiding from American wrath, and you find yourself riffling through the pages of an atlas in search of some of the world's most remote and inhospitable corners.

But the fact remains that "nobody knows where he is," says Alex Standish, editor of the authoritative Janes Intelligence Digest.

Nine months after President Bush said he wanted Mr. bin Laden "dead or alive" and declared war on the Taliban authorities in Afghanistan who refused to hand him over, the most wanted man in the world is still on the run.

And though US officials are now talking more about the dangers posed by midlevel Al Qaeda operatives, their leader, inspiration, and ideologist remains a key quarry.

"It is of critical importance for the US to capture [the top Al Qaeda leadership]," says a former senior US intelligence official who asked not to be named. "As long as they are around, they pose a huge threat, both in terms of organizational recruitment ... and the planning and carrying out of additional attacks."

Washington and its allies have enjoyed some success in their bid to decapitate Al Qaeda. The group's military commander, Mohammed Atef, was killed in a US airstrike on Nov. 14. Another of bin Laden's key deputies, director of foreign operations Abu Zubaydah, was captured in Faisalabad by Pakistani police last March in a joint operation with FBI agents.

But since US and Afghan troops said they had encircled bin Laden in Tora Bora last December, there has been neither sight nor sound of the Al Qaeda founder – who has a $25 million reward on his head – nor of his closest confidant Ayman al-Zawahiri. He has issued no new videos, nor has anyone spotted him communicating by radio, telephone, or computer.

Some analysts believe that bin Laden's silence suggests he was killed in Tora Bora. But no evidence of his death has emerged, and an Al Qaeda spokesman insisted in a statement Sunday that he was alive and well.

"I really want to assure the Muslims that Sheikh Osama bin Laden, with the mercy of Allah, is in a good health, and all rumors about Sheikh Osama's sickness or injuries in Tora Bora is completely inaccurate news," said spokesman Suleiman Abu Ghaith, in an audiotape aired by the Qatari TV station Al Jazeera.

The Washington Post reported yesterday that government analysts had run tests that confirmed the tape's authenticity.

Many US officials believe that bin Laden is still in Afghanistan, seeking refuge in the mountains along the border with Pakistan.

That is the belief, too, of Rohan Gunaratna, author of the recently published book, "Inside Al-Qaeda."

"Bin Laden won't leave Afghanistan," says Dr. Gunaratna. "His stature as a leader would diminish if he did, because he could not expect others to fight the Americans in Afghanistan if he is not there."

Bin Laden is familiar with the border area, since he operated there for several years during the war against Soviet troops, and he enjoys support among the local people, Gunaratna adds.

Alternatively, bin Laden might have slipped across the porous frontier into Pakistan, as have hundreds of Al Qaeda fighters in recent months, according to local residents.

The central government's writ does not run very far in the tribal areas of Northwestern Pakistan, where the conservative Muslim population has long shown sympathy for Al Qaeda. Though Pakistani army troops have been sent to the region, experienced guerrillas would not find it hard to elude them in the cave-riddled mountains.

Sen. Bob Graham, head of the Senate Intelligence Committee, said earlier this week that Washington believes bin Laden is in the tribal area of western Pakistan. But President Pervez Musharraf's government denies that.

"There are a lot of reports about Osama bin Laden being here or there or there," foreign office spokesman Aziz Ahmed Khan said on Monday. "If there is any accurate intelligence report about the whereabouts of these people, I am sure they will be nabbed immediately."

US officials have recently been playing down bin Laden's importance.

"I'm not solely fixated on [Osama bin Laden]," says Lt. Gen. Dan McNeill, commander of US forces in Afghanistan, in an interview with the Monitor. "If [his capture] is incidental in our operations and we get to him, that's fine. I don't have a particular name affixed to what I'm going up against," he added.

That contrasts with the blunt threats Mr. Bush made against bin Laden in the immediate aftermath of Sept. 11. "If he thinks he can hide and run from the United States and our allies he will be sorely mistaken," Bush said in a radio address last September. "Those who make war against the United States have chosen their own destruction."

"The biggest weakness of the antiterror campaign so far has been the failure to target Osama bin Laden and Ayman al-Zawahiri," argues Gunaratna. "As long as they are alive, Al Qaeda will continue to pose a significant and direct threat to US interests."

Bin Laden's importance is not so much as an operational planner, Al Qaeda watchers say, because his group works as a semi-formal network rather than as a hierarchical organization. But "he acts as a symbol, and gives his imprimatur to operations that he legitimizes," argues Mr. Standish, editor of "Janes Intelligence Digest." "He is seen as the individual who, more than anyone else, symbolizes resistance to the superpower."

Other Al Qaeda officials "lack bin Laden's level of charisma and respect and authority," adds Gunaratna. "As long as a man of his stature is alive, he will be able to replenish the human losses and material wastage" by inspiring new recruits.

"Getting rid of the long- term threat means getting rid of bin Laden and Zawahiri," Gunaratna says.

In the meantime, he warns, "bin Laden's character is that wherever he is, he'll be active. Work is prayer for him. It is not in his nature to go into hiding, but rather to plan and prepare."

• Faye Bowers in Boston and Philip Smucker in Kabul, Afghanistan, contributed to this report.