Bukavu, Democratic Republic of Congo (CNN) -- It's been called a forgotten war and its children the forgotten victims.
In the Democratic Republic of Congo's raging conflict, children are caught on both sides as both perpetrators and victims.
In Bukavu, the capital of South Kivu province, schoolchildren were diligently bent over their notebooks but they weren't practicing handwriting or arithmetic. They were drawing traumatic scenes from their past such as villages under attack by gunmen. And some of the children -- until very recently -- were doing the shooting.
The United Nations estimates that tens of thousands of children in the Congo are fighting in armed groups, many of them orphans forced to join the lawless militia that have ravaged this part of Congo.
The classroom is part of a U.N. Children's Fund sponsored rehabilitation center where they are working to show children caught up in Congo's violent conflict that they have the right to a peaceful future.
CNN was invited to film at the rehabilitation center to raise awareness about the plight of children whose lives have been turned upside down by conflict
Casoret Jimmya is the center's most recent admission. He said he joined a rebel militia at the age of 12, after his brother was killed.
"When my brother was killed by a local militia, I knew I had to join an armed group, it's the only way you can protect yourself."
Jimmya spent the last five years moving from one militia to another but after a childhood stolen by combat, he broke free.
"That life of fighting and death, it feels like another person, I don't even remember all the things I did, all the killing. I want a normal life. I want to study. That's why, when I heard about this center, I came."
But it's not just the children. Pappi is a teacher at the center and knows exactly what the buys go through when they arrive. Nine years ago, both his parents were killed in an attack on their village and he too became a child soldier.
"At 14 I was a child soldier, now I'm at university. I'm studying hard. I want to be a human rights lawyer. All these things I tell the children because I want them to know there is a place for us back in normal society. I want them to know they can have a life."
Across town, in the center's other unit, are the victims of the child soldiers - children found abandoned at the scene of attacks. Their parents are missing, either dead or too terrified to come out of hiding yet.
Zarkayo is three. Congolese soldiers brought him in after they chased away militiamen from a village that was being looted.
It is unclear whether his parents are alive. Zarkayo told the nurses at the center his name but hasn't spoken since.
When we come closer to take his picture, he clings crying to his carer. He has graying hair and a swollen belly, both signs of severe malnourishment.
The soldiers tried their best to feed him but they didn't know how long he had lain alone and hungry before the Congolese Army arrived.
The Center's Medical Officer, Simily Valerie, said Zarkayo's story is similar to many others. "When they first arrive it is very bad but we give them milk and we give them love and they slowly get better."
They do the same for the child soldiers also.
"They all have abandonment issues," resident psychologist Rahima Choffy said.
"All of the children here have to learn how to trust again and we do that by showing them love, breaking down the boundaries between them and us and them and each other."
They know they are working against the continuing backdrop of violence and they know some of the children will pick up their weapons again.
But center director Murhabazi Namegebi said he would not allow that to discourage him.
"We work with the children, we work with the armed groups and we work with the government. This is how you build peace, from inside society.
"Six-thousand child soldiers have been through this center since it opened 20 years ago. And the children, they go back to their villages and they tell other children carrying a gun is not the way. And so step by step, peace will come."