Child trafficking, it's a huge concern across Africa. Activists say thousands of children are kidnapped every year - many sold into a life of virtual slavery or something worse. Kenya's capital, Nairobi, has been identified as a center for this horrific trade. Now youngsters there are being offered a new weapon against traffickers. Oliver Jarvis has more.

It sounds like a typical childhood nightmare.

"It was during the night, my father and mum were not at home. Four men came and they took me away. I cried, but they were strong."

But this was a young girl's reality.

Forced by her father to undergo female genital mutilation, the 14-year-old ran from home, but her father found her - he wanted her to get married. She escaped him again - and finally found help from a local NGO.

There is no accurate figure for the number of children trafficked in Africa. Organisations record their own figures. Through survivor stories, they can build up a picture.

"Men were coming in, mostly white men and Arabs. They could come in any time, they could pick anybody they wanted. They used you, you had to do whatever they told you to do - you had no choice."

The International Organisation for Migration lists Kenya's capital Nairobi as a child trafficking hub. Those caught by traffickers often end up as victims of the sex tourism trade and authorities struggle to keep up.

But activist groups are fighting traffickers on a new front. Using education, a Kenyan-based NGO is reaching out to those most vulnerable.

WINNIE MUTEVU AWARENESS AGAINST HUMAN TRAFFICKING, KENYA "As HAART Kenya we were able to come up with a manual, which also has different materials being used. Together with the manual, we have video clips, we have songs that we're using, and different placards. The usefulness for these materials is that it becomes more child friendly and it makes it easier to discuss issues with children on a level that they understand."

These materials teach children the dangers of human trafficking. And the interactive lessons encourage discussions.

LEON OTIENO STUDENT "I like this lesson because it teaches us how we can educate people on human rights, and how to help other children like us so that they can learn that child labour is a bad thing to do."

OLIVER JARVIS NAIROBI, KENYA HAART is planning to provide the materials and lessons in classrooms across the country. But it says authorities also must do more to take on the traffickers.The NGO estimates at best just 2% of Kenyan children who are trafficked ever make it home.