Mexico does not comply with its own laws in how it handles unaccompanied child migrants who arrive in the country fleeing violence in Central America, a Human Rights Watch report said Thursday.

Since the United States pressured Mexico to step up detentions of migrants in recent years to reduce a surge reaching the U.S. border, the number of children detained in Mexico has risen dramatically. Last year, Mexican authorities apprehended nearly 36,000 children, more than half of whom were unaccompanied. It detained 9,600 children in 2013.

In interviews with 61 child migrants, Human Rights Watch researchers were told by only one that officials had informed him of his right to seek refugee recognition, as is required by Mexican law.

Children were not properly screened for possible refugee claims, the report said. On the contrary, it said, the children described immigration officials who warned them of long stays in detention if they applied for asylum. And even if they did want to apply there was no legal assistance to help them navigate the process.

Only 0.3 percent of the unaccompanied child migrants detained in Mexico were granted international protection in 2015, the report said.

"If the interest is enforcement, which it is, meaning arrest, detention and deportation, it is clearly in the interest of individual officials, agents, to make that as easy as possible," said Michael Bochenek, senior counsel to the children's rights division of Human Rights Watch and the report's author. "They are not complying with the law, and as to why they are doing that, that's an open question. There is no question that the incentive is to cut corners."

Mexico's national immigration institute did not respond to a request for comment.

The issue is most acute in southern Mexico, where most of migrant children are stopped. A fraction of the children are transferred to shelters run by a government agency providing support to families, but the majority are held in detention centers to await deportation.

While some children are migrating for economic reasons many are fleeing for their lives, escaping violent homes or relentless street gangs that control many of their neighborhoods in El Salvador, Honduras and Guatemala. Most are believed to be trying to reach the U.S. where they have relatives or expect greater economic opportunities. But Bochenek said that for children simply trying to escape imminent danger Mexico can offer a refuge.