Vietnam's lost children in labyrinth of slave labour
Last year, three teenage boys jumped out of a third-floor window in Ho Chi Minh City and ran as fast as they could until they found help. It was one in the morning and they did not know where they were going.
"I was really scared someone would catch us," recalled Hieu, 18.
Hieu, who did not want to give his real name, is from the Khmu ethnic minority. He grew up in a small village in Dien Bien, a mountainous area in north-western Vietnam, one of the country's poorest provinces and bordering China.
When he was 16 he had a job making coal bricks in his home village when a woman approached him offering vocational training.
"My parents were happy I could go and earn some money," he said.
He and 11 other children from his village were taken by bus on a 2,100km (1,300 miles) journey and put to work in Ho Chi Minh City (formerly Saigon), south Vietnam.
They spent the next two years locked in a cramped room making clothes for a small garment factory with no wages.
"We started at 6am and finished work at midnight," he said. "If we made a mistake making the clothes they would beat us with a stick."
Prostitution, begging and garment factories
Hieu is one of more than 230 child-trafficking victims that the Vietnam-based charity Blue Dragon Children's Foundation has rescued since 2005.
The charity helps children forced into a variety of jobs from prostitution to begging, but in the past year just over a quarter of that number have been rescued from garment factories in Ho Chi Minh City, the country's largest metropolis and industrial centre.
Conditions are often harsh.
"Last year we raided one factory. I think 14 people work, sleep, eat in a small room with the machines," says Blue Dragon's lawyer. "The factory owner only let them go to the bathroom for eight minutes a day, including brushing your teeth, washing, going to the toilet. "
The youngest was 11 and most were from ethnic minorities.
"They are taking kids from central and northern Vietnam because they are assuming those kids can't escape," said Blue Dragon co-founder Michael Brosowski.
"If they get kids from nearby, those kids can just walk out or walk home."
Mr Brosowski believes traffickers are targeting more remote areas such as Dien Bien province because communities there do not know about the risks of human trafficking.
Gangs approach local officials pretending to offer jobs or vocational training to children of the poorest families. Many are happy to send the children away.
Some villages Blue Dragon visit are missing dozens of children.
Parents and officials only realise there is a problem when the charity shows them pictures of garment factories they have raided in the past.
"When they realise the kids are now slaves in sweatshops, they want them back," he said.
Mr Brosowski believes the problem is getting worse, partly because it is so lucrative and other people in the trafficking business want "a piece of the pie", he said.
It also fits a nationwide trend as the rural poor seek jobs in the city. He does not believe the clothes are produced for export, but cannot say for sure.
'Tens of thousands of kids and adults'
Tackling external trafficking has long been on the government's agenda, and Vietnam has been praised for an increase in the number of prosecutions involving overseas gang activity.
A child working in one of the garment factories raided by the Blue Dragon Children's Foundation in Vietnam
Work conditions for children held against their will in garment factories can be harsh and dangerous
According to official figures, a total of about 7,000 people, 80% of whom are women and children, have been trafficked internationally or domestically since 2005.
Independent experts say the number is likely to be much higher.
Children are taken from all over the country to work in brothels in China, South East Asia and Europe.
China's one-child policy has also led to a demand for male babies, which is met partly by Vietnamese mothers selling their infants, but there have also been cases of Vietnamese girls being sold to Chinese men to be impregnated.
Young men or boys are also trafficked to the UK to work in cannabis farms.
Government figures do not give the ratio of external and internal trafficking. However, the scale of the problem within the country is only just emerging.