Updated

Pope Francis has denounced the forced repatriation of unaccompanied children migrants who flee wars and poverty, saying countries should try to meet their needs rather than return them to uncertain futures back home.

Francis took up the plight of child migrants in his annual message for the World Day of Migrants and Refugees on Thursday.

History's first Latin American pope didn't cite specific cases, but the plight of unaccompanied Central American children crossing into Mexico en route to the U.S. has been a concern of Catholic bishops and Catholic grassroots organizations for years.

Mexico now deports more Central American migrants than the United States, a dramatic shift since the U.S. asked Mexico for help in 2014 after a spike in illegal migration, especially among unaccompanied minors. Most Central American migrants, who are fleeing drug and gang violence in Guatemala, Honduras and El Salvador, are deported from Mexico on buses.

In his message, Francis said countries must balance their right to control migratory movements with their "duty to resolve and regularize the situation of child migrants, fully respecting their dignity and seeking to meet their needs when they are alone, but also the needs of their parents."

He warned that children migrants are often led into prostitution, pornography or are enslaved as child laborers. He said more often than not, children are forcibly returned home "without any concern for their best interests" rather than being welcomed and integrated into new countries.

Even detention centers are cause for concern, he said.

"It is not unusual for them to be arrested, and because they have no money to pay the fine or for the return journey, they can be incarcerated for long periods, exposed to various kinds of abuse and violence," the pope said.

Francis visited the U.S.-Mexico border earlier this year and prayed for migrants who died trying to reach the U.S.

In 2014, more than 46,000 unaccompanied minors from Central America crossed into the United States, leading the U.S. government to turn to the governments in Mexico and Central America to try to stanch the flow. In most cases, Mexico holds migrants only long enough to verify their nationalities before sending them home.

According to Mexican government figures quoted by the U.N. children's agency, more than 16,000 migrant children from El Salvador, Guatemala and Honduras were apprehended in Mexico during the first six months of 2016. But thousands still make it to the United States.

While unaccompanied children apprehended in the United States are guaranteed an immigration court hearing, they are not entitled to a court-appointed attorney. A comparison of cases initiated in 2015 showed that by June 2016, 40 per cent of unrepresented children were ordered deported, compared with 3 per cent of children who had lawyers.