The Syrian regime may be their sworn enemy, but rebels fighting to bring down President Bashar al-Assad say they pay hard cash to government agents for guns and bullets.
For Syria's plethora of armed opposition groups, obtaining weapons is a constant struggle. Furious with the West for failing to provide heavy weaponry, they say they have little choice but to look to alternative sources.
In a country where national service is compulsory, and a conflict where brothers fight on opposing sides and rebels defect from the armed forces, they say it is not difficult to find a "middleman" or an "old friend" to help.
"We buy from Assad spies and on the market," said Major Abu Mahar, puffing on a French cigarette over coffee at a gym requisitioned by his network of fighters as a base in the northern city of Aleppo.
He claims to lead 200 men who conduct "special missions" against Assad's forces. But like other units, they are poorly armed with machineguns, rocket-propelled grenades, sniper rifles and home-made rockets and bombs.
Seven Kalashnikovs hang upside down from hooks and a bucket of bullets sits in the corner of Abu Mahar's office, which overlooks the mirror-lined workout room where bodybuilders used to flex their pecs.
Quietly spoken and hunched over in a leather jacket, he defected this summer from the air force. And like other rebels, he still has associates in various branches of the government military and security.
Abu Mahar says a bullet costs 110 Syrian pounds ($1.60) to buy from the regime, compared with $2 on the market, declining to specify where that market might be.
He claims that most of his group's ammunition supplies come from the shabiha, the term used to refer to state-sponsored militia hired by the government.
"We buy them from double agents, they need the money. The shabiha's God is money. They don't care about anything else. If you give them money they'll even sell you their own mother," he said.
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"They have open access to army, police and intelligence bullet stores. They're saving up for when the regime falls," he smiled into his salt-and-pepper beard.
But Abu Mahar is evasive about where and how often the exchanges take place. He says his network uses a "pointman" or an "old friend," and they do not meet face to face.
Rebels seem unperturbed about bankrolling their enemy, particularly when the West has declined to provide heavy weaponry and there is no prospect of a NATO-enforced no-fly zone that was so vital in toppling Libya's Moamer Kadhafi.
"They've already taken our money for the last 40 years, our gold, our minds, what difference does it make?" shrugged one member of the main rebel group, the Free Syrian Army (FSA), in northern Syria near the Turkish border.
For Yussef Abud, a commander in the FSA's Tawhid Brigade, it's a matter of survival although he claims to have bought regime bullets only "once or twice."
"What can I do? Sometimes I don't have enough weapons or bullets. I don't like it, but without these bullets and weapons, many FSA will be killed," he told AFP.
Rebels also take guns from soldiers they kill on the battlefield, while others who defect from the regime often manage to smuggle their weapons out with them.
Sitting guard in an old sports complex on the Aleppo front line, Mohammed Abu Issam al-Halabi, 49, claims to have bought his Kalashnikov "from bad guys in the regime" for $1,000 when he decided to become a "mujahid" eight months ago.
"You can't buy these on the market and I need a weapon. What can I do?"
The former factory boss, with a bushy beard and black Islamic bandana round his head, told AFP that before the uprising the gun would have cost only $200-$300.
Across the road, Lieutenant Ahmed Saadeen, 24, agrees that buying armaments from the regime is right.
Like many rebels, he angrily criticises the apparent refusal of the West and the Gulf to provide Syria's rebels with anti-tank and anti-aircraft weapons.
"Where else can we buy them?" he snapped, before sprinting away to dodge sniper fire.