Most of those fighting the regime of President Bashar Assad are ordinary Syrians and soldiers who have defected, having become fed up with the authoritarian government, analysts say. But increasingly, foreign fighters and those adhering to an extremist Islamist ideology are turning up on the front lines. The rebels are trying to play down their influence for fear of alienating Western support, but as the 18-month-old fight grinds on, the influence of these extremists is set to grow.
On Monday, a U.N. panel reported a rise in the number of foreign fighters in the conflict and warned that it could radicalize the rebellion.
The Syrian government has always blamed the uprising on foreign terrorists, despite months of peaceful protests by ordinary citizens that only turned violent after repeated attacks by security forces. The transformation of the conflict into an open war has given an opening to the foreign fighters and extremists.
Talk about the role of foreign jihadists in the Syrian civil war began in earnest, however, with the rise in suicide bombings. U.S. National Director of Intelligence James Clapper said in February that those attacks "bore the earmarks" of the jihadists in neighboring Iraq.
Rebel commanders are quick to dismiss the role of the foreign fighters and religious extremists, describing their numbers as few and their contribution as paltry.
Col. Abdel-Jabbar Aqidi, a top rebel commander for the Aleppo area, told The Associated Press there were maybe 500 jihadis involved in the battle for Aleppo, while a report from the Quilliam Foundation, a London-based think tank studying extremism, estimated a total of 1,200-1,500 foreign fighters in all of Syria.
Other commanders estimated that at most, jihadis, whether local or foreign, made up no more than 10 percent of the fighters.
While this is a small amount compared with the thousands of rebels estimated to be battling the regime, Peter Harling of the International Crisis Group warns that the religious extremists will have an influence on the rebellion.
"I think numbers are irrelevant," he said, adding that the extremists are a "very important phenomenon in many ways. Their presence is very divisive, whether there are many or not."
"They are certainly visible, and this increasingly shapes the complexion of the opposition in ways that are not negligible," Harling said.
Reflecting their extreme sensitivity to the topic, the media center on the Syrian-Turkish border investigated and questioned any journalists they discovered who had written about foreign fighters in Syria.
"My brother died in this revolution. This revolution means everything to me, and if the world thinks that al-Qaida is involved, it is finished," said Nader, a young rebel with the media center who declined to give his last name.
The media center investigated and questioned any journalists they discovered who had written about foreign fighters being involved in the rebellion.
Most of the rebels fighting in the north come from the countryside and have always been more traditional and religious than the more cosmopolitan urbanites of Aleppo.
Rebels often wear the beards associated with religious Muslims and pepper their conversations with references to their faith, but that does not necessarily mean they subscribe to ultraconservative views.
"Having a beard is not a symbol of extremists. It just means we're religious, like a woman wearing a headscarf or a Christian wearing a cross," said Abdel Malik Atassi, a young rebel in the town of Marea, as he gestured to his bearded comrades.
Atassi also noted that the fighters tend to be more religious.
"As a fighter, I am constantly close to death, so yes, I am more religious and I want to follow the prophet's traditions more closely in case I die," he added.
Rebel leaders like Abdel Aziz Salameh, one of the top commanders in the countryside, said that while he hopes for a future government system based on Islamic law, it will ultimately be the people's choice.
"We don't let the foreign fighters spread their way of thinking in our home," he told AP. "We don't need foreign fighters. We have 100,000 men who want to fight, but we don't have weapons for them."
- Penny-farthing owner keeps on riding
- Ready or Not: Rio Olympics open doors at...
- Police: Munich suspect was obsessed with mass...
- Brie Larson confirmed as 'Captain Marvel'
- Authorities: Munich shooter planned attack...
- Clinton's turn: Guide to the Democratic...
- Baton Rouge to continue to mourn officers...
- Civil-rights marchers: US still needs to...
- Sarah Silverman: Bernie-or-bust Dems... 49
- Is Bernie Sanders an atheist? 44
- Trump says Russia should find Clinton's... 42
- Obama boosts Clinton: Carry her like... 40
- Clinton wins historic nomination,... 37
- After turmoil, Sanders, Michelle Obama,... 31
- Dems' division, emails roil party on... 28
- Democrats and Republicans double-down... 26