Aleppo, Syria - Abdel Razzaq's 'military academy' is located in a former school in northern Syria's Aleppo province. It is where local boys come to receive two hours of training a day for three months before being sent off to the front.

Eager to join their older brothers and fathers on the frontline of the Syrian civil war, the teenagers readying themselves to fight with the rebels are oblivious to the international laws prohibiting child combatants.

"When they arrive here, they are children. By the time they leave, they are killing machines," says Abdel Razzaq, the 38-year-old former army sergeant who trains them.

He teaches his students how to handle a Kalashnikov, or AK-47 assault rifle, the weapon most commonly used by the rebels, as well as how to overcome fear and never to hesitate when the time comes to kill.

"Children are the best soldiers I know. They obey every command. An adult asks questions and answers back. But the children, they question nothing," Abdel Razzaq says.

And with families willingly bringing their boys to be trained, the academy does not struggle to find students.

Sixteen-year-old Bashar was signed up by his brothers. "I want to avenge the death of my father [a Free Syrian Army fighter]," he explains.

On the Salaheddine frontline in Aleppo, Abdel Khader is an example of the sort of fighter many of these boys hope to become. A red scarf frames his boyish face and although he is too young to legally drive, he says: "Don't let my age fool you. I've been fighting for five months and have killed a number of soldiers. Every day I watched on television how the army was killing innocent people, and I didn't want to stay at home waiting for them to kill us also."

This article first appeared in the August 2014 issue of the Al Jazeera Magazine. Download the magazine for iPads and iPhones here, and for Android devices here.