Source: Thomson Reuters Foundation

"I stay because I don't have a choice. I'll put up with it until I can't take it anymore."

Wearing a pastel-coloured dress embroidered with a tatty trim and speaking almost in a whisper, 17-year-old Chancelle looks like she should be in school.

But, since the age of 15, she has instead been going into isolated huts or simply to the fields to sell sex for money.

"Each week, I would meet with three or four men," the teenager, who declined to give her real name, told the Thomson Reuters Foundation.

Chancelle fled north to Chad in 2014 after her father was killed by armed militants in her native Central African Republic (CAR), where Muslim Seleka rebels and Christian and animist "anti-balaka" militias have been fighting since 2013.

A spike in violence in CAR over the last year has forced a fresh wave of refugees into Chad, the world's third least-developed country, which is also weighed down by drought, floods and conflict with the militant group Boko Haram.

The teenage girl imagined life would be easier in the vast central African country where her parents were born.

But she has gone from trading goods at a market in CAR to selling her body in Chad for as little as 250 CFA francs ($0.44) to men who sometimes beat her.

She does not even insist on condoms.

"I don't want to risk it, in case he goes to another girl," she said. "Some days, I don't eat at all. Some days, I have only 50 CFA, 100 CFA to put something in my belly."

'I DON'T HAVE A CHOICE'

Chancelle is one of thousands of so-called returnees living in Danamaja, a muddy site in southern Chad that hosts displaced people who claim to have family roots in the country but lack paperwork to prove their nationality.

For centuries, trading and cattle herding families freely criss-crossed the international border drawn up by European colonialists, which was little more than a line on a map.

When the war erupted in CAR, widespread violence and ethnic killings made life there impossible for many.

Chad responded by sending planes in 2013 to rescue fleeing Muslim returnees from CAR - which has produced at least seven waves of mass exodus since 2003.

About 70,000 officially recognised refugees from CAR live in 20-plus villages and six camps across southern Chad, often complaining of shortages of food and medicine.

There are a similar number of returnees, the United Nations (U.N.) Office for the Coordination of Humanitarian Affairs says.

Most do not have any papers to prove their existence. This means they are not entitled to the same basic assistance as refugees who fled the same war, sometimes even the same town.

Chancelle, who has never been to school, said even her food ration card was washed away by the rains months ago, and getting a replacement has proven impossible.

The young mother has no one to support her or her 2-year-old child, whose father left Danamaja - a remote strip of land some 600 km south of the Chadian capital - without a trace.

"I stay because I don't have a choice," she said. "I'll put up with it until I can't take it anymore."

'LEGAL GHOSTS'

Returnees visited by the Thomson Reuters Foundation received less aid than refugees, with worse shelters and medical care.

They risk joining the ranks of an estimated 10 million stateless people worldwide - "legal ghosts" with no nationality who are deprived of basic rights that most people take for granted.

Stateless people are often denied healthcare and education. Children may be forced into marriage or the armed forces as minors and, if accused of a crime, prosecuted as adults because they cannot prove their age.

Chad started issuing returnees with national identity cards in 2014, which allow them to move around freely to seek work, use local health facilities and open bank accounts.

Chancelle would also be able to send her child to school.

But the machine producing the cards broke down and funding shortages mean only about 6,000 returnees in southern Chad have received them, the U.N. refugee agency (UNHCR) said.

Elise Mbainar, a social worker with a local charity, Initiative Humanitaire pour le Developpement Local, estimates about 200 girls in Danamaja sell their bodies for sex, although there are no official figures.

Some are just 12 years old, she said, including girls living with their parents.

"It's the conditions here that push them to do this," Mbainar said, looking at the ramshackle huts made of tree stumps and bamboo shoots, tied together with rotting strips of fabric, and covered with a patchwork of tarpaulin sacks.

"It's a life that the girls don't want – that no one wants."

($1 = 561.1300 CFA francs)