When resurfaced Friday in a 26-minute videotaped speech, his most important message was one left unsaid: We have survived.
The last time bin Laden showed his face to the world was three years ago, in October 2004. Since then, 's core leadership -- dubbed al-Qaeda Central by intelligence analysts -- has grown stronger, rebuilding the organizational framework that was badly damaged after the U.S.-led invasion of , according to counterterrorism officials in , the United States and .
It has accomplished this revival, the officials said in interviews, by drawing on lessons learned during 15 years of failed campaigns to destroy it. In that period, bin Laden and his followers have outfoxed powerful enemies from the Soviet army to the Saudi royal family to the CIA.
Dodging the in Afghanistan after the Sept. 11, 2001, attacks, al-Qaeda Central reconstituted itself across the Pakistani border, returning to the rugged tribal areas surrounding the organization's birthplace, the dusty frontier city of . In the first few years, Pakistani and U.S. authorities captured many senior leaders; in the past 18 months, no major figure has been killed or caught in Pakistan.
Al-Qaeda Central moved quickly to overcome extensive leadership losses by promoting loyalists who had served alongside bin Laden for years. It restarted fundraising, recruiting and training. And it expanded its media arm into perhaps the most effective propaganda machine ever assembled by a terrorist or insurgent network.
‘Not just as a loose bunch of guys’
Today, al-Qaeda operates much the way it did before 2001. The network is governed by a shura, or leadership council, that meets regularly and reports to bin Laden, who continues to approve some major decisions, according to a senior U.S. intelligence official. About 200 people belong to the core group and many receive regular salaries, another senior U.S. intelligence official said.
"They do appear to meet with a frequency that enables them to act as an organization and not just as a loose bunch of guys," the second official said.
Operatives are organized into cells with separate missions, such as fundraising or logistics, and may know the identities of only a few individuals in their circle to prevent infiltration, Pakistani officials said. Most leaders are based in Pakistan, although many travel to Afghanistan and occasionally farther afield, to , , , the region and .
Counterterrorism officials were slow to grasp the resurrection of al-Qaeda Central. For years, many U.S. and European intelligence officials characterized it as a spent force, limited to providing inspiration for loosely affiliated regional networks. Bombings in Europe and the were blamed on homegrown cells of militants, operating independently of bin Laden.
Victory declared too soon?
On June 24, 2003, declared al-Qaeda's leadership largely defunct. At a summit, Bush praised Pakistan's Gen. , crediting his country with apprehending more than 500 members of al-Qaeda and the .
"Thanks to President Musharraf's leadership, on the al-Qaeda front we've dismantled the chief operators," Bush said. Although bin Laden was still at large, his lieutenants were "no longer a threat to the United States or Pakistan," Bush added.
Six months later, Musharraf was nearly killed in an assassination attempt by al-Qaeda operatives. Shortly afterward, a group of al-Qaeda leaders held a summit of their own in the Pakistani region of , where they plotted fresh attacks thousands of miles away in , including targets in and financial institutions in the United States, according to Pakistani officials.
Pulling the strings
Many U.S., Pakistani and European intelligence officials now agree that al-Qaeda's ability to launch operations around the globe didn't diminish after the invasion of Afghanistan as much as previously thought. Further investigation has shown, for example, that al-Qaeda's leadership, with bin Laden's direct blessing, made the decision to activate sleeper cells in in 2003, prompting a wave of car bombings and assassination attempts that the Saudi government has only recently brought under control.
From hideouts in Pakistan, according to court testimony and interviews, bin Laden's deputies ordered attacks on a Tunisian synagogue in 2002, a British consulate and bank in in 2003, and the London transit system in 2005.
U.S intelligence officials also blame the al-Qaeda brain trust for orchestrating dozens of other failed plots, including a plan to blow up transatlantic flights from Britain in August 2006.
"All this business about them being isolated or cut off is whistling past the graveyard," said Michael Scheuer, a former analyst who led the agency's unit assigned to track bin Laden. "We're looking at an organization that is extraordinarily adept at succession planning. They were built to survive, like the Afghans were against the Russians."
A failed strike After nightfall on Jan. 13, 2006, an unmanned Predator aircraft guided by the CIA fired missiles at two houses in the northwestern Pakistani village of Damadola, a few miles from the Afghan border.
The target was a dinner celebrating the Muslim holiday of Eid al-Adha. CIA officials had received intelligence that , al-Qaeda's deputy leader, had been invited to attend.
The missiles destroyed the houses and killed more than a dozen people. Zawahiri was not among them, but Pakistani officials soon said the fatalities included several other high-ranking al-Qaeda leaders.
Musharraf identified one of the dead as Midhat Mursi al-Sayid Umar, an Egyptian who had overseen al-Qaeda's research into chemical weapons and carried a $5 million U.S. government bounty on his head.
Musharraf and other Pakistani officials said those buried in the rubble also included Abu Obaidah al-Masri, the Egyptian chief of the al-Qaeda military wing that plots attacks in the West; , a field commander for al-Qaeda in Afghanistan; and Zawahiri's son-in-law, Abdul Rahman al-Maghribi.
U.S. and Pakistani officials now say that none of those al-Qaeda leaders perished in the strike and that only local villagers were killed. The $5 million reward for Umar's capture remains on offer. Masri has continued to rise in the al-Qaeda structure, U.S. officials say, and six months after his supposed death was helping in the failed effort to put bombs aboard airliners flying from Britain.
Mahmood Shah, who at the time of the strike was Pakistan's security chief for the region, said intelligence for the Predator mission stemmed in part from the interrogation of another al-Qaeda leader, Abu Faraj al-Libi, who had been captured eight months earlier in the city of Mardan, also in Pakistan's northwest.
At the time, Shah said, U.S. and Pakistani officials thought merely that the timing of the strike was slightly off and that they had barely missed Zawahiri. Now, he said, he thinks Zawahiri and the others were never there. "I just think the information was not correct," he said.
Hitting a wall
The only publicized success in the nearly 20 months since the Damadola attack came on April 12, 2006, when Muhsin Musa Matwalli Atwah, an Egyptian al-Qaeda operative indicted for involvement in the 1998 attacks on U.S. embassies in , was killed in .
Otherwise, the search for al-Qaeda's leaders in Pakistan has hit a wall. Shah said information concerning their whereabouts has grown scarcer and less reliable. By his account, Pakistani security officials haven't come across a single trace of bin Laden in the tribal areas. Occasionally, they have received tips regarding Zawahiri and others, he said, but only several weeks after the trail has run cold.
"We'd hear about their presence two months after the fact. It's just not actionable intelligence," Shah said. "This inner core has absolutely stopped using electronic technology to communicate with each other. That is why the Americans have such trouble finding them."
On Jan. 30, 2006, two weeks after the Damadola missile strike, al-Qaeda released a videotape on the Internet in which Zawahiri taunted his pursuers. "Bush, do you know where I am?" the Egyptian radical said. "I am among the Muslim masses!"
Al-Qaeda's 'deep bench' A major factor in al-Qaeda's resurgence has been its ability to swiftly replace fallen or captured commanders.
told Congress in November that the core leadership had benefited from a "deep bench of lower-ranking personnel capable of stepping up to assume leadership responsibilities." Many are veteran jihadists who have fought in Afghanistan and conflicts elsewhere for decades.
Intelligence officials and analysts said al-Qaeda's central command remains dominated by Egyptians, primarily associates of Zawahiri, who formally merged his Egyptian Islamic Jihad organization with al-Qaeda in 1998.
One Egyptian who has taken on a bigger role is , an accountant by training who served as bin Laden's financial manager during his exile in in the 1990s. In May, al-Qaeda announced that Yazid had been appointed its overall leader in Afghanistan and liaison with the Taliban.
Yazid, 51, was an original member of al-Qaeda's Shura Council and served time in an Egyptian prison with Zawahiri in the early 1980s after both were convicted of participating in the assassination of Egyptian President Anwar Sadat.
Although he disagreed with bin Laden over the Sept. 11 attacks -- calling them a tactical mistake that resulted in the Taliban's fall from power -- Yazid remains close to the Saudi emir and is trusted by other jihad groups, said Yasser al-Sirri, an Egyptian political exile and director of the London-based Islamic Observation Center.
"Bin Laden appointed him as a conciliatory figure," Sirri said in an interview. "It's because of his credibility. He gets along well with the Pashtuns, with the Taliban -- he gets along well with everybody."
Fresh faces gain influence
Several other fresh faces in the leadership are former members of the Libyan Islamic Fighting Group, a now-defunct network that used to operate at arm's length from al-Qaeda.
Among them is the nom de guerre of a longtime jihadist who fought Soviet troops in Afghanistan, spent two years in prison in Saudi Arabia for covert activities there and organized a failed plot to overthrow Libyan ruler Moammar Gaddafi in the mid-1990s.
He began to work closely with bin Laden in 1999 and impressed al-Qaeda's command by leading the retreat from in 2001 after the U.S. invasion of Afghanistan, said Noman Benotman, a former member of the Libyan Islamic Fighting Group.
"The Saudis and others said, 'Who the hell is this guy?' They were impressed," Benotman said in an interview in London. "He can create operations. He can lead on the front lines. He knows when to attack, when to withdraw."
Abu Laith al-Libi has run training camps in Afghanistan in recent years for al-Qaeda and orchestrated a suicide attack on the U.S. air base in Bagram, killing 23 people, during a visit by in February, according to U.S. military officials.
, a Libyan believed to be in his late 30s, has meanwhile acted as a liaison between al-Qaeda's leadership in Pakistan and , a predominantly Sunni insurgent movement that is believed responsible for some of the deadliest bomb attacks on Shiite civilians in Iraq and is one of the U.S. military's fiercest foes. The group professes loyalty to bin Laden; intelligence analysts are divided as to whether he exercises real control over it.
Rahman has also operated as a bin Laden emissary to militant groups in North Africa that joined forces in January to form .
Words from 'the clouds' Much remains unknown about the internal workings of al-Qaeda Central. As with the old Soviet leadership in , U.S. analysts scrutinize public statements issued by the network for clues on who wields influence.
One figure attracting interest is a Libyan known as , who gained notoriety after he and three other al-Qaeda prisoners escaped from a high-security U.S. military prison in Bagram in July 2005.
Since then, he has appeared on more than a dozen videos produced by al-Qaeda's media arm. His speeches and treatises are so numerous that some analysts speculate he is being groomed to join bin Laden's inner circle. "Abu Yahya al-Libi is now the most visible face of al-Qaeda, surpassing al-Zawahiri, and in fact all of the jihadists," said Ben Venzke, chief executive of IntelCenter, a private terrorism research group that does work for the U.S. government.
In his videos, Abu Yahya al-Libi dresses the part of a gun-toting holy warrior but has made his reputation as a religious hard-liner. He frequently criticizes other Muslims as heretics; favorite targets include Shiites, and the Saudi royal family.
"He's young, but he's very smart," Benotman said. "For his career, the sky's the limit."
Since 2000, al-Qaeda has run its own media production company, al-Sahab, which means "the clouds" in Arabic, an allusion to the misty mountain peaks of Afghanistan.
Harnessing the Web
Until two years ago, al-Sahab was dependent on broadcasters such as the al-Jazeera satellite television network to air its videos and could distribute only short clips on the Internet. But then it achieved a spectacular breakthrough. Taking advantage of technological advances and bandwidth expansion, it began posting videos directly on the Internet, relying on an anonymous global network of webmasters to shield their electronic tracks.
In 2005, al-Sahab released 16 videos. This year, it has produced four times that number. Quality has improved markedly, with most videos now including subtitles in several languages and sometimes 3-D animation.
"If you want to stop al-Qaeda on the communications front, you should concentrate on their IT manager instead of Osama," said Muhammad Amir Rana, director of the Pak Institute for Peace Studies, a research group in , Pakistan, that studies militant groups.
Al-Sahab can now record and release videos with astonishing speed. When Pakistani forces stormed 's on July 10, resulting in more than 80 deaths, Zawahiri responded the next day with an audiotaped speech, calling the raid "an act of criminal aggression."
Covering their tracks
Al-Sahab mixes low-tech and high-tech tricks to prevent spy agencies from blocking its releases or tracing videos back to their source, said Evan F. Kohlmann, a -based counterterrorism analyst.
The videos are routed through a chain of couriers who hand-deliver them to computer gurus, probably in Pakistan, he said.
They, in turn, electronically send the files to others around the world who upload them to free or hijacked Web sites.
"The process of tracing this stuff back is not that easy," Kohlmann said. "They've created breaks in the distribution chain, both electronic breaks and human breaks."
A protective network In July, U.S. intelligence agencies published a report concluding that al-Qaeda Central had regrouped in remote northwestern Pakistan, aided by a 2005 decision by the Pakistani government to declare a truce with Taliban forces and withdraw troops from the tribal area of Waziristan.
Latif Afridi, a Pashtun tribal elder, said that many places along Pakistan's border with Afghanistan have been effectively taken over by foreign militants, mostly Uzbeks, Tajiks, Chechens and Arabs. Although they are not all associated with al-Qaeda, bin Laden's network has been able to rely on them for protection, he said.
"We have al-Qaeda, we have Taliban, we have foreigners, and we have Pakistani-trained militant groups that have been banned," Afridi said in an interview in Peshawar. "They're running the show."
Pakistani and U.S. intelligence officials said the number of militant training camps has surged along the border. But unlike al-Qaeda's fixed camps in Afghanistan before 2001, they consist of small groups that gather for a few days for firearms or bombmaking practice before disbanding, making them hard to detect.
‘The good hunter hunts on foot’
The truce between the Taliban and the collapsed in North Waziristan in July and in a month later. Since then, Pakistani forces have reentered the tribal areas and resumed clashes with the Taliban and other militants.
But Asad Durrani, a retired chief of Pakistan's powerful spy agency, the Inter-Services Intelligence bureau, said it would take more than military intervention to capture al-Qaeda leaders.
Durrani said U.S. bombing campaigns along the Afghan-Pakistani border had thoroughly alienated civilians who otherwise might help root out al-Qaeda commanders. "The first instinct you Americans have is military power -- dropping bombs," he said. "This was absolutely 100 percent guaranteed not to succeed, and it's continued that way for the past six years."
He said it would take a concentrated, methodical approach to find bin Laden and his deputies, relying on human intelligence and simple detective work.
"If they are there, sit back, be patient," Durrani advised. "The good hunter hunts on foot."
Special correspondent Munir Ladaa in Berlin and researchers Alice Crites and Julie Tate in Washington contributed to this report.