In a Lagos suburb, 22-year-old Omo huddles over her battered cell phone, scrolling through text messages to find the name of the Russian city where she was coerced into prostitution.

It was two years ago and she had just finished her exams to enter university when her mother introduced her to an agent promising a sales job in Russia. She agreed to go hoping for a better future. "I wanted to assist myself and my family, because I really wanted to go to school," she said.

When she arrived in Pyatigorsk, a mountain city with a renowned health resort, her travel documents were taken from her and she was told she would be selling her body.

"They said if I don't do it they will kill me," she said, staring at the floor. "It was hell."

Nigeria, Africa's most populous country with 170 million people, is a regional hub for human trafficking, and more assistance is needed to help those who escape the exploitation to find a stable place back in Nigeria, say experts who work with survivors.

Nigeria tops the list of non-EU citizens registered as trafficking victims, according to the European Commission's 2015 Eurostat report.

"Nigeria figures as one of our top priority countries of origin," Myria Vassiliadou, the EU Anti-Trafficking Coordinator, told The Associated Press. To stop the exploitation cycle, reintegration assistance is as important as working to discourage Nigerians from initially being sent overseas to work as prostitutes, she stressed.

"People leave as vulnerable people and come back as vulnerable people," said Vassiliadou. "What stands between them being trafficked again is reintegration support."

As many as six out of 10 trafficked women in European capitals are Nigerian, estimates Nigeria's National Agency for the Prohibition of Trafficking in Persons. The agency says it has rescued 8,006 people since it started in 2003. Support for survivors when they return voluntarily or are deported back is crucial. Many face stigma and even rejection by their families and finding work and housing is a challenge, according to experts.

Like many Nigerians who are trafficked, Omo was sent into exploitation by a family member. She insisted on not giving her full name to avoid further stigmatization.

"They said I should bear it," she said, when she called her family for help. Desperate, she turned to a friend in Lagos, who found a flyer by an anti-trafficking organization in Lagos run by Roman Catholic nun Patricia Ebegbulem.

With the help of Ebegbulem, the International Organization for Migration and local police, Omo returned to Nigeria in March 2014. When her family shunned her, Omo lived for a few months in Bakhita Villa, the Lagos shelter run by Ebegbulem where she learned computer skills and looked for a job.

Omo returned to Benin City, her hometown, after relations with her family improved. She is looking for work in order to save money to go to university, to study international relations in order to work to prevent child trafficking, she said. Occasionally she travels to Lagos to assist the shelter by speaking about her experience to raise awareness.

Resettlement funding from the International Organization for Migration depends on the country where victims were exploited.

"Some countries don't give you a penny to help settle them," said Ebegbulem. "If you don't have anything to reintegrate them with, if they don't get that opportunity, they end up on the streets again." Ebegbulem has worked with survivors of trafficking since 1996, when she visited Italy where she saw a large number of Nigerian women working as prostitutes on the streets.

Although many harrowing tales of exploitation and abuse have been widely publicized in Nigeria, the flow of women continues. In Nigeria, lack of economic opportunity and education, poverty and gender-based violence make people vulnerable to trafficking, according to agencies working to combat the industry.

"Now some of them know what they are going for," said Ebegbulem, highlighting a change in recent years, as some Nigerians willingly go for sex work abroad. "But they don't know the extent, they don't know the dangers involved."