LONDON — In an audio message from a hide-out in South Asia this month, an Al Qaeda chief did something new: He sang the praises of an ethnic group that once barely registered in the network.
"We consider the Muslims in Turkey our brothers," said Mustafa Abu Yazid, the network's operations chief. Lauding Turkish suicide bombers killed in recent attacks near the Afghan-Pakistani border, he declared, "This is a pride and honor to the nation of Islam in Turkey, and we ask Allah to accept them amongst the martyrs."
The message is the latest sign of the changing composition of Islamic extremism, anti-terrorism officials and experts say. The number of Turks in Al Qaeda, long dominated by Arabs, has increased notably, officials say. And militant groups dominated by Turks and Central Asians, many of whom share Turkic culture and speak a Turkic language, have emerged as allies of and alternatives to Al Qaeda in northwestern Pakistan.
"We are aware of an increasing number of Turks going to train in Pakistan," said a senior European anti-terrorism official who asked to remain anonymous because the subject is sensitive. "This increase has taken place in the past couple of years."
Turkey's secular tradition and official monitoring of religious practice for years helped restrain extremism at home and in the diaspora. But the newer movements churn out Internet propaganda in Turkish as well as German, an effort to recruit among a Turkish immigrant population in Germany that numbers close to 3 million.
"We are seeing almost as much propaganda material from these Turkic groups as we are from Al Qaeda," said Evan Kohlmann, a U.S. private consultant who works with anti-terrorism agencies around the world. "Turks were perceived as moderate with few connections to Al Qaeda central. Now Germany is dealing with this threat in a community that could be a sleeping giant."
Germany is especially vulnerable because it has troops in Afghanistan. The threat could also intensify in other countries with Turkish populations, such as France, Belgium and the Netherlands, whose anti-terrorism agencies focus on entrenched extremism in large North African communities.
And the implications are serious for Turkey, a Muslim ally of the West and a longtime gateway to battlegrounds in the Middle East and Asia.
As Al Qaeda's multiethnic ranks burgeoned in the 1990s, Turks trained in Afghanistan and fought in Bosnia-Herzegovina and the Russian republic of Chechnya. In 2003, Al Qaeda suicide bombers killed 70 people in attacks on synagogues and British targets in Istanbul, Turkey's largest city.
Despite Turkey's population of more than 70 million, however, Turks were once among the smallest contingents in the network.
"I used to tell the Germans they are very lucky because you couldn't find much radicalization among Turks," said Zeyno Baran, a Turkish-born expert on Islam at the Hudson Institute, a think tank in Washington. "No one was paying much attention to Turks because they were considered the safe group."
Although Turkey works closely with Western anti-terrorism forces, some officials say it devotes more energy to fighting Kurdish separatists. Baran expressed concern that the moderate Islamist government in power since 2002 has lowered its guard.
"With the government's reluctance to talk about the problem of Islamist ideology, Al Qaeda and groups like that seem to think there's an opening in Turkey and with Turks," said Baran, whose forthcoming book is titled "The Other Muslims: Moderate and Secular."
Combat-hardened Central Asians have adopted a global agenda and tapped a new recruitment pool. Only five years ago, Kohlmann said, there was little need for Turkic-language translators to monitor extremist Internet traffic; now they are in demand.
"These groups are trying to establish their pedigree and catering their propaganda to Turkic speakers who don't speak Arabic or Pashto," the dominant language in the Afghan-Pakistani border region, he said. "Their media organizations are saying: We are the equivalent of Al Qaeda for Turks."
The Islamic Jihad Union, an Uzbek-led group, has alternately competed and worked with Al Qaeda. The organization trained and directed two Turks and two German converts who have agreed to plead guilty in a 2007 bomb plot against U.S. targets in Germany.
Last year, the group announced that another recruit, a 28-year-old Turk born in Bavaria, killed two U.S. soldiers in a suicide bombing in Afghanistan.
During the same period as the attack last year, half a dozen French and Belgian militants were training in Al Qaeda compounds in the Waziristan region of Pakistan. The subsequent description by a French trainee of the nationalities of the fighters he encountered departs from the commonly held image of an essentially Arab movement.