By Andrew Walker
BBC News, Abuja
Some parents turn a blind eye to the abuse of their children
Solomon and Rebecca (not her real name) are two of the longest-staying residents at a shelter for trafficked children in Nigeria's capital, Abuja.
Before they turned 10 years old, they were taken from their homes in Nigeria's south-eastern Abia state on a week-long journey across the Bight of Guinea to Gabon in a canoe.
There, they were put to work on the streets by their "uncles" - neighbours or friends of their parents from their home village.
They had promised to look after them and send them to school, but they were instead subjected to a daily routine of beatings and verbal abuse.
This movement of child labour is common in Nigeria. Last month, 105 children were rescued from the back of a 15-seater minibus as they were being driven to an Islamic school 400km away from their homes in northern Kano state.
Last year the authorities rescued 1475 children. Nobody knows the true number of children trafficked, but it may be thousands.
The country's anti-trafficking authority say it is a clear case of abuse. The way the children were packed one on top of another into a tiny bus showed they were being trafficked, they believe.
But the children's parents say they were sending their children out to a traditional Koranic school, known as "Tsangaya", the Hausa word meaning "village" or "traditional".
Rebecca and Solomon's ordeal began with the promise of going to school.
"My daddy died and my uncle came from Gabon," said Rebecca, 13. "He said he would take me to school in Gabon. My parents believed him because he'd taken my brother to school there. But he tricked them. He brought pictures of my brother in school uniform."
But as soon as they arrived in Gabon her uncle and his wife revealed what was in store for her. She went to work selling sachets of drinking water at traffic lights in town and washing plates at a street kitchen.
Between 2004 and 2006, NAPTIP returned 757 children to Nigeria from abroad
Last year 1,475 were rescued
Traffickers can get 14 years in jail
Only 12 have so far been prosecuted
Sources: Unicef, Naptip
"If in a day I made 2,000 naira ($17) I told him that was enough to send me to school but he said: 'No more about school,' and he beat me. He used a rope to tie me and sometimes he lifted me up."
She slept in the marketplace and ate scraps of food from the rubbish.
She later worked in their house cleaning and washing. If she made a mistake, she was savagely beaten.
"If I missed a plate, eh! I missed myself. In all the five years I was there, food - I never knew food."
Solomon, who was brought to Gabon three years earlier, has a similar story. He is now 19 years old.
"I kept asking my uncle when he was going to put me into school and then he said if I asked again he would beat me," Solomon said.
Instead he was forced to sell leather on the street. He had to give his "uncle" 3,000 naira ($25) every day. If he did not earn that amount, he was beaten.
On one occasion he was supposed to give the money to a prostitute his uncle had slept with the night before, but he didn't make enough.
"The man took electric iron, plugged it in and allowed it to over red, and used it on my body. When something is getting difficult like that, there is no way you can even cry because if you are even pleading for cry you will not get."
Solomon has no wish to return to his home village
He ran away but was brought back to the house and beaten again.
Both Rebecca and Solomon escaped by running to the Nigerian embassy in Libreville.
They were rescued four years ago by Wotclef, the Women Trafficking and Child Labour Eradication Foundation, and they have lived in the Abuja shelter since.
They do not want to go home to their villages in Abia state now, as they go to school in Abuja, and have friends there.
Solomon wants to be an artist and musician, Rebecca says she loves maths and wants to be a businesswoman.
"But I won't sell anything. I have done enough selling," she says.
In Kano, the parents of the 105 rescued in the bus denied their children had been trafficked.
"It is part of the tradition to send children away. We believe they will be less able to be distracted from their studies if they are away from us," one of the parents told journalists when their children were handed back to them by the Emir of Kano, a respected regional leader.
But the National Agency for the Prohibition of Traffic in Persons (Naptip) says it is likely they were being moved south to be used as farm labour in the forthcoming planting season.
The head of a Tsangaya school in Kano agrees.
"It seems suspicious," said Malam Goni Yahuza.
"Parents do send their children away to learn the Koran, but usually there are only around five children to every teacher. Also students don't start past the age of eight, so to have 15-year-olds among them is suspicious.
"I would not sanction what has happened here and parents should be careful. They must provide for their children's needs."