(CNN) -- Feras races across a dusty crossroads, firing his AK-47 wildly at regime forces somewhere down the road ahead of him. This is Aleppo, and he is one of many rebel fighters there, slogging it out street by street, often not seeing their enemy or much progress for weeks.
But Feras is different in a way that has sparked great fears and controversy. Feras is Libyan. He is one of Syria's "foreign fighters."
The presence of foreigners among the ranks of Syria's rebels has been seized on by nearly all sides to suit their purposes.
The Syrian government says they are proof the rebels are extremists and terrorists. The rebels sometimes point to them as a sign that they haven't had the outside help NATO gave their Libyan counterparts and have instead had to rely on foreign militants with genuine experience of battle, and sometimes let in people who they would not normally have asked to fight alongside.
Among the rebel ranks are, according to whom you listen to, al Qaeda, foreign jihadis, Salafis seeking a radical Islamist state, and then plain old freedom fighters -- Muslims seeking to support their Arab brothers in this brutal battle.
Feras says he is in the last category. He arrived a few months ago after meeting a Syrian in Tripoli.
His motivation was simple, he told journalist James Foley: "We lived this moment, we felt this moment, so as it was in Libya. You cannot say this is not freedom fighters. They protested to get free. You know this moment. Like it was in Libya."
He was strongly dismissive of the western response to Syria's revolution, saying they had dismissed the Syrian rebel movement as a militia.
"The governments around the world... I don't know why they only watch, they don't give support. They don't give a no fly zone."
He staunchly rejected claims that foreign fighters are radicals or have links to al Qaeda. "I'm only a student. I left my money, my student, my family. We are not al Qaeda. We are not coming to break this country, we're coming to help."
He says his politics are simple. He wants an Islamic government for Syria but only, he says, because most of its people are Muslim anyway.
This is for him a fight to help another people, after which he wants to return home to Libya. And he rejects the more radical ideology of Salafists.
He knows about loss himself. His brother was killed in Libya's civil war, and he still wears his black shirt. And since he has been in Syria, a Libyan friend of his has also been killed in the fighting.
Ducking in and out of Aleppo's ruins, and narrowly missing being hit by a tank shell, it's clear he is willing to endure great risk to this end. In fact, he tells Foley he is willing to die for this cause.
Experts differ on how serious the threat from these foreign militants is.
Professor Ahmad Moussalli, an expert on Islamic movements from the American University of Beirut, said he believed they were radical, often had links to al Qaeda, and were a serious threat.
He said he did not think the rebels had "any benefit in having them, but I think at this point because of their weaker training and weaponry they may need them to fight against the Syrian regular army."
But his concerns were for the dividend that these foreigners would seek when the fighting ends.
"If you assume the fighting is going to finish, they are there to stay and what we might witness is something like Yemen where the foreign fighters will be able to control certain areas or cities," he said.
The United Nations' International Commission of Inquiry on Monday stated it believed there was "an increasing presence of foreign elements, including Jihadist militants, in Syria," and intimated they were having a radicalizing effect on the rebel movement.
Yet other analysts said their role was less seminal. Emile Hokayem, Senior Fellow for Regional Security at the International Institute for Strategic Studies, said he believed the foreign militants remained marginal in their influence and were still left out of some of the more complex rebel operations.
"They are realistically about 2,000-3,000 in number. Foreign fighter does not equate with jihadi. Not everyone is driven by jihadi ideology."
He added that the rebel movement was itself increasingly aware of being tarred by the brush of extremism. "The Syrian rebels are aware of the political downside of jihadis in these groups", he said.
Veteran Syria analyst Joshua Landis said one of the most important roles that these foreign elements had played so far was that of "scaring the Gulf states and the USA from further involvement. An obvious thing to do [to help the rebels] is to send Stinger [surface to air] missiles. That would change the balance of power but nobody wants to do that," he said, citing concerns such potent weaponry could fall into the wrong hands.
But he added fears of radicalism were also being used by foreign powers to excuse a lack of intervention.
"It is cover for a lot of other things. Syria is a poor broken down country, a swamp. Obama is clear is that he does not want to get into Syria. They are reaching for every pretext under the sun. They do not want to get into another major nation building project. So they are cutting Syria off."
As dust from explosions fills the street, Feras can be seen talking calmly into a walkie-talkie. He has spent much of his 20s surrounded by civil war, the Arab world's upheaval that will affect his generation.
But he says he is not radicalized, and in fact rejects the militancy that held sway over his teenage years.
The question for Syria is how long will the moderates among the foreigners remain, and, as the brutality continues and Western intervention eludes Syria, how swiftly will extremism blossom?