Guillaume Briquet / AFP / Getty Images Center: A Turkish fighter of the jihadist group Al-Nusra Front, bearing the flag of Al-Qaeda on his jacket, holds position with fellow comrades on April 4, 2013 in the Syrian village of Aziza, on the southern outskirts of Aleppo.

The men appeared confused. They huddled around a rotisserie-chicken stand in the Syrian city of al-Bab, 11 of them, dressed in the black tunic and trousers of the Islamic State of Iraq and Syria (ISIS), an al-Qaeda affiliate that is fighting against the Syrian government of Bashar Assad. Back from the front lines, guns slung from their shoulders, they tried, in vain, to communicate with the shopkeeper. Their Arabic was nonexistent; their English fractured. They consulted with one another in Albanian. Was the chicken halal, appropriate for observant Muslims to eat? Another foreigner, an adviser to an international aid agency who happened to speak Albanian, solved their dilemma. He assured them that the chicken, in this most conservative part of Muslim Syria, would be nothing but halal. Satisfied, they placed their orders.

“It was just so bizarre to see a Kosovar Albanian asking if the shawarma was halal,” said the aid worker, laughing, as he recounted the incident over Skype. He spoke on condition of anonymity to protect his organization. “I’ve seen Chechens, Norwegians, Belgians and even a guy who said he was Somali but who spoke in a thick Birmingham accent. These fighters are coming from everywhere.”

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While Westerners make up about 10% of the foreign fighters in Syria, according to counterterrorism analysts, European and U.S. officials have raised the alarm about increasing numbers of their citizens taking up the fight. Most join al-Qaeda-affiliated groups like ISIS, which are dominated by seasoned jihadis from South Asia, North Africa and the Persian Gulf. The fear, say concerned officials, is that when fighters return home, they bring with them battlefield skills and extremist ideologies, or worse — intent to do violence in their home countries. Andrew Parker, head of the U.K.’s domestic intelligence service, MI5, said in a parliamentary hearing last week that British citizens in “the low hundreds” had been going to Syria to fight with al-Qaeda. The danger, he said, is when al-Qaeda elements in Syria “meet British citizens who are willing to engage in terrorism, and they task them to do so back at home, where they have higher impact.”

While al-Qaeda might be focusing on Assad at the moment, the group is already discussing taking the fight beyond Syria’s borders, according to U.S. Congressman Mike Rogers, chairman of the House Intelligence Committee. “They’re talking about conducting external operations, which is exactly what happened in Afghanistan, which led to 9/11,” he said at a foreign policy forum on Oct. 22. In Europe, Syria-related arrests have begun. On Nov. 5 six ethnic Albanians were arrested in Kosovo on suspicion of “preparing a terrorist act against the safety and constitutional order” in Kosovo, according to an arrest warrant seen by the Associated Press. Two of the men are also suspected of attacking American Mormon missionaries in the capital, Pristina. Authorities believe that at least two of the men have recently returned from Syria.

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Hans-Georg Maassen, head of Germany’s domestic intelligence agency, told Reuters that at least 220 German citizens had gone to Syria. Belgian authorities estimate that 150 of their citizens have joined the fight. So too have 150 ethnic Albanians, according to Kosovar officials; at least a dozen of those have been killed in Syria, as reported by the Associated Press. In the U.S., a Pakistani immigrant was caught in a FBI sting trying to go to Syria to join the Nusra Front, another al-Qaeda group named by the U.S. State Department as a terrorist organization. “Syria has become the premier location for jihad,” says Shiraz Maher of the International Centre for the Study of Radicalisation and Political Violence, a London-based think tank focused on understanding and analyzing violent extremism. “Al-Qaeda groups in Somalia and Yemen are saying, ‘Don’t forget about us, we need fighters too.’”

Unlike Iraq or Afghanistan, where Western troops led the war effort, the fight in Syria is far less controversial for would-be jihadis who might be put off by the idea of confronting their own nationals on the battlefield. It’s also a lot easier to get to. Syria is on Europe’s doorstep. All it takes is a flight to Turkey and a contact to help cross the porous, 560-mile-long border. German citizens do not even need a passport to enter Turkey; an ID card suffices. “Once you are there you can be quickly integrated into brigades, and you can fight alongside people with the same language,” says Maassen.

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The Syrian jihad has taken on an almost summer-camp feel for some young Muslim men, says Maher, who maintains regular contact with several British fighters in Syria. It’s a rite of passage that gives them a sense of community while testing their manhood. “Going out to the fight gives them a kind of euphoric high,” he says, pointing out that unlike some of the less well-funded moderate rebel groups, the al-Qaeda affiliates can offer fighters a far more comfortable experience. Their food, clothing and shelter are taken care of, they have wi-fi in well-appointed camps and they are given weapons. They take selfies with their balaclavas and post them on Facebook and Instagram. And for believers, the religious aspects of the fight ensure hero status. “Either you win the battle, or you die and you become a martyr and go to heaven. So it’s victory or paradise,” says Maher. The only risk is when they bring that philosophy home.