The Algerian partner, the Salafist Group for Preaching and Combat, had fought the Algerian government in a barbaric civil war for almost a decade. But Zawahiri said the new alliance had different targets in mind. "Our brothers," he said, "will be a thorn in the necks of the American and French crusaders and their allies, and a dagger in the hearts of the French traitors and apostates." View graphic

Zawahiri's statement was the latest sign of how, with al-Qaeda's help, the Algerian network has rapidly transformed itself from a local group devoted solely to seizing power at home into a global threat with cells and operations far from North Africa.

Since 2003, the group known by its French initials GSPC has emerged as an umbrella for radical Islamic factions in neighboring countries, sponsoring training camps in the Sahara and supplying streams of fighters to wars in Iraq and Chechnya, according to counterterrorism officials and analysts in Europe and North Africa.

The network also has planted deep roots in Europe. In the past year, authorities have broken up cells in France, Germany, Italy, Spain and Switzerland, including one group that allegedly plotted to shoot down an Israeli airliner in Geneva.

On Sept. 1, the French Anti-Terrorist Coordination Unit issued a statement classifying the group as "one of the most serious threats currently facing France," Algeria's former colonial master. Ten days later, the assessment was given fresh urgency by Zawahiri's videotape, timed for the fifth anniversary of the Sept. 11, 2001, attacks in the United States. In it, he noted that Osama bin Laden, al-Qaeda's founder, had given his personal approval to the "blessed union" between the Algerian network and al-Qaeda.

Responding to Zawahiri's declaration, French Prime Minister Dominique de Villepin said there was a "real and permanent" risk to France, in part because of its military involvement in Lebanon and Afghanistan, as well as its policy of forbidding Muslim girls to wear head scarves in public schools.

Pierre de Bousquet de Florian, the head of France's domestic intelligence service, added: "For our Islamist adversaries, our country is frankly in the Western camp -- the 'crusaders' in their words -- and we will be spared nothing."

Overcoming Differences
Al-Qaeda forged its alliance with the GSPC in spite of a long history of feuding with Algerian radicals.

The Algerian conflict, which has claimed an estimated 200,000 lives since 1991, at first attracted enthusiastic support from Islamic radicals around the world, including Zawahiri and other future al-Qaeda leaders. They sent money, fighters and supplies to the guerrillas, seeing the war as an opportunity to replace Algeria's secular, military-backed government with a fundamentalist Islamic state.

But their zeal was shaken when Algerian rebels led by another terrorist network, the Armed Islamic Group, or GIA, began slaughtering thousands of civilians. The GIA subscribed to an Islamic ideology called takfir , a belief that any Muslim who does not embrace strict, medieval codes of conduct is an apostate deserving of death.

Bin Laden, who was living in Sudan at the time, believed that killing fellow Muslims was counterproductive. So he sent an emissary to Algeria to demand that the GIA change its approach and pledge loyalty to the fledgling al-Qaeda network, according to European intelligence officials. The GIA refused.

As the massacres continued, bin Laden's allies in London and elsewhere wrote scathing denunciations of the Algerian group, a rejection that persisted for years.

The Salafist Group for Preaching and Combat -- its name is derived from a branch of fundamentalist Islam -- was founded in 1998 by a splinter group of Algerian rebels who wanted to reduce the number of civilian massacres. It quickly eclipsed the GIA, but it still struggled to win support from abroad.

That started to change after al-Qaeda launched the Sept. 11 attacks. With its territorial base in Afghanistan in jeopardy, al-Qaeda's leadership began looking for safer places to relocate.

In the fall of 2001, according to French and Algerian officials, bin Laden dispatched a Yemeni deputy to Algeria for talks with the radical group. The emissary was reported killed in September 2002 by Algerian security services, but his presence in Algeria marked a turning point, they said.

"Until 2001, the GSPC wasn't trusted by the rest of the international jihad," said Louis Caprioli, former director of international counterterrorism for the DST, the French counterintelligence service. "That's when the GSPC started to become international. It used to be focused solely on Algeria."

On the second anniversary of the Sept. 11 attacks, a leader of the Algerian group posted a statement on the Internet pledging the group's allegiance to al-Qaeda for the first time, adding: "We strongly and fully support Osama bin Laden's jihad against the heretic America." In March 2005, a successor leader, Abu Musab Abdel Wadoud, issued a similar statement praising bin Laden.

Until recently, al-Qaeda's leadership had offered cautious or tepid responses. In the summer of 2005, bin Laden referred to "our brothers" in the Algerian network in a long statement on audiotape, but otherwise has not publicly embraced the group.

It became clear, however, that an alliance could bring benefits to both sides, analysts said. If the Algerians could win al-Qaeda's endorsement, it would erase their network's pariah status in radical Islamic circles, making it easier to raise money and logistical support. In turn, al-Qaeda would gain a local affiliate and an operational foothold in North Africa.

"The leadership of al-Qaeda doesn't have a secure base left anywhere else in the world," said Liess Boukraa, a terrorism expert and author in Algiers. "So al-Qaeda needs the GSPC at the logistical level. The GSPC needs al-Qaeda at the ideological level."

Al-Qaeda has pursued this strategy in multiple Muslim countries, partnering with local underground groups in an effort to extend its name and influence. In Iraq, al-Qaeda teamed with Abu Musab al-Zarqawi's insurgent group, prevailing on him to change its name to al-Qaeda in Iraq. The Kurdish group Ansar al-Islam and various organizations in Kashmir have similar ties with bin Laden's movement.

Analysts said the shift by the Algerian organization toward a global strategy was a tacit admission that its original goal -- seizing power in its home country -- had failed. The network continues to attack government targets in Algeria almost weekly, but it has taken heavy losses in recent years and is confined to remote areas in the mountains and desert.

Estimates of the number of active GSPC members, who constitute almost all of the remaining fighters against the Algerian government, run from 500 to 1,200 -- a sharp drop from the 40,000 Islamic extremists who took up arms against the government in the 1990s.

Algerian Interior Minister Noureddine Yazid Zerhouni said last month that Algerian security forces had killed or captured 500 Islamic fighters over the past year. In addition, about 250 members of the GSPC and other extremists have accepted the Algerian government's offer of political amnesty under a national reconciliation program, he said.

Mounir Boudjema, an expert on Algerian terrorist groups and editor of the newspaper Liberte, said the Salafist radical group is weaker than ever at home.

"In terms of strategy, they have lost," Boudjema said in an interview in Algiers. "The population doesn't want to have them anymore. The people in the villages refuse to give them blankets or water or food. The whole logistical network is falling apart."

Training and Support
Even as it struggles in Algeria, the GSPC has rapidly extended its reach elsewhere in North Africa.

With al-Qaeda's backing, the network has partnered with other radical groups, including extremists in Morocco, Libya, Tunisia and Mauritania, according to Arab and European counterterrorism officials. There was little overlap among such factions in the past, officials said, but now many have turned to the Algerians for training and support.

"The message we get is that al-Qaeda has given delegation to the GSPC to coordinate their operations in the Maghreb region," said Chakib Benmoussa, the Moroccan interior minister.

"Al-Qaeda's objective is to have a base in the region of the Sahel," he added, referring to the remote stretch of North Africa that borders the southern edge of the Sahara and covers such impoverished nations as Mali, Mauritania and Niger.

In June 2005, about 150 of the Algerian group's fighters from different countries attacked a Mauritanian military outpost, killing 15 soldiers. Another of its cells kidnapped 32 European tourists in the Sahara in 2003 and reportedly received a $5 million ransom from the German government for their release.

Counterterrorism officials said the network operates training camps in the Sahara and Sahel that cater to fighters from countries bordering Algeria, but also recruits from Europe. The camps are small and temporary, consisting of four-wheel-drive vehicles and a few instructors who teach bombmaking and guerrilla tactics, said a U.S. counterterrorism official who has studied the network and spoke on condition of anonymity.

"It's all mobile and on the run. They'll rendezvous in a wadi for four or five days, then disperse," the official said, using an Arabic word for a streambed that is usually dry. "We're very much concerned about it. It's more than just a few guys. If you add it up, it's a substantial number of folks."

Many veterans of the North African camps have traveled to Iraq, where they make up one of the biggest contingents of foreign fighters battling U.S. and Iraqi forces, according to counterterrorism officials and analysts.

According to a study released in March by the Saudi National Security Assessment Project, an adviser to the Saudi government, North Africans make up about 30 percent of foreign fighters in Iraq, with 22 percent from Algeria alone. U.S. military officials and independent analysts said other estimates have shown somewhat lower numbers of North Africans, but agreed that Algerians and the Salafist group are playing key roles in the conflict.

"The GSPC, they saw the handwriting on the wall," the U.S. counterterrorism official said. "If they just stuck to fighting the Algerian government, all they would be is a minor thorn in their side. So they had to reach out."

In Europe, meanwhile, the group has revived dormant networks of Algerian radicals who emigrated after the outbreak of the civil war 15 years ago, counterterrorism officials said.

In 1994, Algerians from the GIA hijacked an Air France jet and planned to crash it into the Eiffel Tower, but a commando unit stormed the plane and rescued passengers. The next year, another GIA cell carried out bomb attacks on the Paris subway.

The same group planned attacks during the 1998 World Cup in France. But French police disrupted the plots and initiated a continent-wide round of arrests that effectively knocked out the organization on European soil.

In reconstituted form, the Algerian underground in Europe is no longer fighting solely for a national cause. That has enabled it to recruit large numbers of Tunisians, Moroccans, Syrians and other extremists who do not hold a stake in the Algerian conflict, said Xavier Raufer, a terrorism specialist at the University of Paris and a former French intelligence officer.

In July, for instance, German authorities arrested a 36-year-old man of Moroccan descent in the northern city of Kiel and charged him with recruiting fighters to go to Iraq. Prosecutors said he was a member of al-Qaeda and knew members of the Hamburg cell that carried out the Sept. 11 attacks. Last November he had traveled to Algeria to receive explosives training at a GSPC camp.

In March, eight Moroccans and a Tunisian were arrested in Casablanca and accused of planning attacks in Italy, with targets including a church in Bologna and the Milan subway system, Moroccan and Italian officials said. The cell was charged with working on behalf of the GSPC and taking orders from a deputy in Algeria.

Many of the Salafist group's foot soldiers in Europe have never been to Algeria, but are motivated to join the network because of Islamic anger over conflicts in Iraq, Afghanistan and Israel, Raufer said. "For them, it's an easy time," he said of the recruiters. "When they preach, a lot of people are furious. A lot of Muslims are outraged at what's going on."

Staff writer Colum Lynch in New York contributed to this report.