By Claire Marshall BBC correspondent in Chia, near Bogota

The number of children fighting in Colombia's civil war has doubled over the last five years, according to a new report.

All sides recruit children to fight for them

The country now has one of the highest numbers of child soldiers anywhere in the world, some of whom are recruited as young as eight years old.

Those children who are captured or who manage to desert the rebels are taken to government safe houses such as the one I am visiting in Chia, near Bogota.

Just walking up to the drive the green mountains soar up away there to my left.

To my right some children are working on their own bit of vegetable patch, and just over there somebody is milking one of the many cows.

Walking up the steps into the house now, the radio is playing.

Everything is designed to make these children feel really at home.

New start

There is a big welcome sign on the walls, which are painted a warm orange.

There is also a poster stating the mission statement here.

Behind this facade, this tough facade that they have gained in the bushes and in the jungle, there's a little kid that's eager for love Manuel Manrique, music teacher

Its heading is "Choice" - "choose love instead of hate, choose to laugh instead of cry" and there is a whole list of things here.

This is the place where these children are going to be given the chance to start a new life.

Twenty children have come to live here.

They all have harrowing stories of their lives fighting as child soldiers in Colombia's bloody civil war.

A new report out from Human Rights Watch shows that around one in four of those involved in the conflict are under 18.

Most join voluntarily, many to escape a life of crushing poverty and misery.

As part of her morning duties, Carolina reaches into the chicken shed to look for eggs.

She is not really called Carolina. She cannot be named for her own safety, as rebel deserters are usually shot.

Carolina was raped as a child. When ELN guerrillas knocked at her door, she went with them, believing she could get revenge on the man who did it.

She was just 15-years-old.

Speaking quietly, twisting the rings on her hand, she says that she bitterly regrets leaving her family for a life of violent conflict.

"The battles were very hard," she tells me.

"I felt that death was very close - as if it was the last moment of my life. It was horrible."

No childhood

Colombia's 40-year-old civil war is being fought by numerous different factions, essentially divided between left-wing guerrillas and right-wing paramilitaries.

Colombia's civil war knows no rules

All of these irregular groups have dramatically stepped up their recruitment of children over the last five years.

Esteban turns up the music and runs a hand through his shaved hair, which is wet with gel.

He joined the leftist rebel group FARC because he had had an argument with his girlfriend and was bored at home.

He is not certain how many people he killed before he was 18. He thinks it was about five.

"Sometimes you felt scared, we all did," he says.

"But you fire yourself up and you feel yourself shooting, and you say to yourself 'just carry on'."

He also cannot be identified because the FARC shoot deserters, whatever their age.

Three months ago, he was fighting heavy gun battles but now he helps to care for the animals.

Small haven

Nicolas Cuellar is from the Colombian Institute for Family Welfare, the group which runs these safe houses.

"They have lived very hard, very tough things - some things that a child just doesn't live through normally - they just don't have a childhood," he says.

"It's not just the combat between their group and the military forces, it's all the situation that they live in - being tortured or seeing their friends being killed or being tortured by one group or another and maybe sexual exploitation and that sort of thing."

In the safe house, a music teacher plays a game with the children.

They have to be taught how to laugh again.

Manuel Manrique is one of their instructors:

"Behind this facade, this tough facade that they have gained in the bushes and in the jungle, there's a little kid that's eager for love, for comprehension, and they end up embracing you and kissing you because they find in you somebody, something that they're eager to have - love."

Carolina and Esteban and the others sit in a circle, singing along.