LIBREVILLE (AFP) – At the sprawling Mont-Bouet market in Libreville, dozens of children heave bags of cement on their shoulders. Others wander around for hours, desperately trying to sell dried fish or cakes.
Their parents are nowhere to be seen: these children are virtual slaves illegally lured from west African states to oil-rich, equatorial Gabon.
Lari, now 22, was only 11 when she was taken from her native Togo by a stranger who claimed to be her uncle.
She was told that she would be reunited with her mother, who had abandoned her at birth, and was taken by boat to Gabon.
But Lari had been tricked, and she was sent to work for a rich Togolese family living in Gabon, placed there by her "uncle".
So began her gruelling new life as a house maid: up every day at dawn, preparing the meals, acting as a nanny for the family's baby, and when all that was done, shopping every evening for food.
During her time working for the family, Lari said she never received any money. Instead it was taken by her so-called guardian.
"I never earned a cent," Lari told AFP. Her guardian would visit "to take money at the end of each month, he never told me how much", she said.
"Wherever I worked, it was the same."
Lari calculated that the family owed her 2.6 million CFA francs (almost 4,000 euros), money that she has never been given.
In 10 years, more than 700 children have been rescued from exploitation as virtual slaves and repatriated, according to the UN Children's Fund.
However, "nobody knows how many are exploited because they have no travel papers, they don't have formal jobs... Everything is informal," said UNICEF representative in Gabon, Michel Ikamba.
To bring children to Gabon, a country of 1.6 million people seen as an El Dorado in other parts of Africa, child traffickers use the "channels of clandestine immigration", Ikamba explained.
Overloaded boats full of west Africans fleeing poverty and unemployment in Benin, Togo, Nigeria or Mali land on beaches near the coastal capital Libreville after nightfall.
The Gabonese navy intercepted one such vessel in 2009 which was carrying 300 illegal immigrants, including 34 children destined for exploitation who were handed over to UNICEF.
-- Parents given promises and cash --
The children arriving in Gabon have no idea what awaits them.
Young girls often end up as domestic servants or prostitutes and the boys are given manual labour, toiling from morning to night in sweltering heat.
Their parents back in the home country were won over by vain promises and a fistful of money.
"They tell them that their children will go to school and then they give them 20,000 CFA francs (30 euros, $39) to encourage them," said Sister Marguerite Bwandala, who runs two centres in Libreville opened by the Roman Catholic charity Caritas.
"The networks are well organised. The trafficker places them, often with people from their home country, to take up jobs such as vulcanising rubber (to give it greater strength and elasticity) or selling groundnuts, and he collects their wages," Sister Marguerite said.
But it does not stop at financial exploitation: according to UNICEF, children are often subject to violence, including sexual abuse by the father in the family that takes them in.
For teenager Sonia, who was just six years old when she arrived from Ketou, a village in southern Benin, violence was the norm.
After each day at work, "I was tired, the old woman beat me very hard. She hit me across the face. They said that I was their daughter, but it wasn't true", said Sonia. Finally, she fled.
Rare are the children though who manage to break free of the grip of their new families, who are their only reference point in a nation where they are foreigners and have no papers.
As she grew up, Lari was passed from employer to employer.
She says her final job, which lasted eight years, was the worst. "I was made mistress of the house. I had to look after the husband all the time, I couldn't go to bed until he came home, even if it was at four in the morning."
"His wife accused me of things that weren't true. When she lost money, it was always my fault. She searched my things and when she found nothing, she tortured me, she beat me to make me confess," she added.
Much worse was to follow.
"She accused me of sleeping with her husband's brother. Three times she took me to the doctor to prove that I was still a virgin."
Gabon has started taking steps to crackdown on the trafficking of children. It has joined UNICEF in launching a training programme in five towns to unite magistrates, army officers, police and social workers in fighting against such exploitation.
Closer cooperation will also make it easier to repatriate children, said UNICEF's Ikamba.
Lari has at last found a way out, with paid employment as a nanny in Gabon. She is hoping to save up enough to open a business back home.
At a Caritas-run centre, there is also hope. Fourteen-year-old Edith is training to be a hairdresser. The nuns hope that she can qualify in Gabon and avoid further exploitation.
"She's doing well," said Sister Marguerite. "She has even learned to read and write here."