Just this past week, Chad's government admitted there are child soldiers in its army. But schools along the troubled eastern zone, near Sudan, have long known that, when a child suddenly disappears from the classroom, chances are he may have joined one of the fighting groups. Phuong Tran visits one school, 60 kilometers from the Sudanese border, to see how its educators are trying to stop children from becoming young soldiers.

Until recently, this primary school in Habile, Chad, had 300 students.

But, after waves of violence forced families from surrounding villages to seek safety in Habile, more than 1500 students now fill the blue classroom tents in the desert.

Many of the teachers come from the displaced community and most of the new students have never before attended school.

Here, the students face bigger challenges than just memorizing their multiplication tables.

Attacks often force the school to cancel classes.

To help track students during these waves of violence, Jesuit Relief Services' School Project Director Gonzalo Sanchez Teran helped create a student registration system that started last month.

Teran says this is one way schools can protect children from the many armed groups that look for young soldiers.

"We can control when they are not there," he said. "We follow what is going on. What happens with the kid [who] has not gone to school one, two days? Why is he not there? Go to visit the families. Talk to them. Talk to the teachers and try to get him back to school."

He says schools in Chad do not normally have registration processes, which has made it hard for teachers to track students.

For example, in the nearby community, Gouroukoum - home to more than 10,000 displaced Chadians - one man remembers when his grandson did not come home from school, three years ago.

The 57-year-old man does not give his family's name, to protect his grandson.

The man says he learned his grandson, then 14-years-old, had secretly joined the Chad national army.

The year before, Janjaweed militia had killed the boy's father.

After having lost his only son, this man says there is nothing he can do to bring home his only grandson from the fighting.