Editor's note: Peter Bergen is CNN's national security analyst, a director at the New America Foundation and the author of "Manhunt: The Ten-Year Search for bin Laden -- From 9/11 to Abbottabad." Tim Maurer is a policy analyst at New America.
(CNN) -- In August, al Qaeda's propaganda arm released a video starring the German rapper Deso Dogg.
Wearing combat fatigues and standing next to a waterfall in Syria, Deso Dogg raps in German calling on others to join the jihad and "to make an effort for Paradise."
Deso Dogg, whose real name is Denis Cuspert, is one of several dozen German citizens who have fought in Syria.
Their move to Syria marks an important shift in the focus of global jihadists. Videos by German militants training with groups associated with al Qaeda during 2009 and 2010 were invariably taped in the Afghanistan-Pakistan border region.
That region now is largely shunned by foreign militants partly because of effective CIA drones strikes and partly because Syria is now the destination choice for jihadists from around the world.
Deso Dogg is one of the many thousands of foreign fighters who have been drawn to the jihad in Syria against the regime of Bashar al-Assad over the past three years.
This group includes an estimated 800 to 900 from Europe, mostly from Germany, the United Kingdom, France, the Netherlands and Belgium. A handful of Americans have also fought in Syria.
The concern, of course, is that these militants will swap business cards and will acquire arms training and bomb-making skills and will return to Western countries and carry out acts of terrorism.
This is what happened after the war in Afghanistan during the 1980s. Arab veterans of those wars formed the heart of al Qaeda and affiliated groups. Osama bin Laden fought in the Afghan War against the Soviets and then founded al Qaeda, which subsequently, of course, launched the 9/11 attacks. The failure to pay adequate attention to the so-called "Afghan Arabs" such as bin Laden proved an expensive one for the United Sates and her allies.
Could Syria be a new Afghanistan? Maybe.
Last month, for instance, British authorities arrested militants who were allegedly planning a terrorist attack. Two British officials who work on counterterrorism issues told us that that the militants had traveled to Syria.
The 37-year-old Deso Dogg was born in Berlin. His mother is German and his father from the West African nation of Ghana. As a teenager, he became politicized during the first Gulf War, joining anti-American demonstrations in Berlin. "We marched, shouted and burned the American flag," Cuspert recalled.
Cuspert joined Berlin street gangs and became a popular artist in the German gangsta-rap scene, known by his nom de rap "Deso Dogg" and touring with other rappers such as DMX.
After surviving a car accident, he started questioning his lifestyle and turned to Islam for answers. In 2010, he ended his career as a rapper. Deso Dogg changed his name again to "Abu Talha al-Almani" and his rap songs became nasheeds, Islamic devotional songs.
Cuspert's nasheeds were posted on jihadist websites and became popular among al Qaeda supporters.
The ex-rapper went on to become one of the key figures in the militant Millatu-Ibrahim group in Germany.
The group was banned by the German government last year and several of its members, including Cuspert, moved to Egypt to avoid possible arrest by German authorities.
Cuspert's whereabouts remained unclear for many months until the video was released in August showing him to be in Syria and rapping about the duty to "go into battle."
Some 6,000 to 10,000 foreign fighters from more than 80 countries are believed to have traveled to Syria since the beginning of the conflict to join the rebels who aim to topple al-Assad's regime.
Close to 800 of those foreigners are from Saudi Arabia. Tunisia and Libya are the next highest contributors, according to residents and analysts, but Chechnya, Kuwait, Jordan, Iraq and the United Arab Emirates have also seen citizens join the rebel forces in Syria.
Not all of these fighters have joined al-Qaeda linked groups in Syria, but it is likely that many of them have done so because they are generally Sunni militants who are drawn to the conflict for religious reasons.
Canadian news reports estimate the number of Canadian citizens fighting in Syria range from a few dozen to as many as 100. An American filmmaker, Bilal Abdul Kareen, who lived with an Islamist group in Syria for a year said he met with 20 to 30 Canadians.
Experts say the number of Americans fighting in Syria is likely less than 10. Eric Harroun, a former U.S. solider, was charged this year with conspiring to use a rocket-propelled grenade in Syria, and he admitted to fighting with the al Qaeda affiliate group, al-Nusra.
Nicole Mansfield of Flint, Michigan, was killed in May by Syrian government forces who claimed she was fighting with an al Qaeda linked insurgent group.
How to prevent the foreign fighters in Syria fomenting acts of terrorism around the world?
The United States and its allies should make a careful effort to find out the identities of the foreign fighters who have joined the jihadist groups fighting in Syria. And the U.S. should make clear to countries such as Saudi Arabia, which is supplying hundreds of Saudi fighters in Syria, that encouraging this kind of militancy could create a "blowback" problem in the Middle East in the form of terrorism directed at Arab regimes.
As for the former Deso Dogg, in September a jihadi forum released a statement saying that the German ex-rapper had been wounded by an air strike in Syria.
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