By Richard Cowan
WASHINGTON (Reuters) - President Barack Obama's emergency response to Central American children arriving in the United States without permission has spawned aggressive law enforcement efforts in Mexico where authorities rarely weigh humanitarian concerns, according to a report released on Thursday.
Last year, a flood of "unaccompanied minors" - children traveling without their parents - from El Salvador, Guatemala and Honduras rushed to the southwestern U.S. border with Mexico.
Fleeing criminal gangs and drug-related violence, the numbers of children rapidly escalated last summer, eventually totaling nearly 63,000 for the 10 months ended July 2014.
At the time, Obama said quick action by the United States was needed to avert a humanitarian crisis. He unveiled a multi-pronged response, including an intensified effort, coordinated with Mexico, to secure borders.
The result is a 51 percent drop in child apprehensions from last year, according to government figures.
But the report by the Migration Policy Institute, a non-partisan think tank, concluded that "both the U.S. and Mexican enforcement systems raise concerns about the protection of vulnerable children."
The State Department had no immediate comment.
For those children who made it into the United States, asylum requests are slowly winding through immigration courts.
But with Mexico taking on more responsibility for capturing immigrants before they get onto U.S. land, their quest for asylum more often is falling on deaf ears.
"The very high ratio of deportations to apprehensions in Mexico indicates limited humanitarian screening and inadequate due-process protections," the report said.
Wendy Young, who heads Kids in Need of Defense, a Washington-based non-profit, said, "Virtually none of the children who are apprehended and returned by Mexico are first screened for refugee protection."
The report comes as Europe grapples with hordes of people fleeing violence in Syria, Afghanistan and other countries. As in Central America, human smugglers have arranged unsafe trips that have resulted in scores of people dying.
Broadly, the Migration Policy Institute concluded that Obama's 2014 initiative has had a "squeezing of the balloon" effect, with more of the undocumented children being kept away from the United States but little being accomplished to deal with core economic and social problems in Central America fueling the migration.
The study said that for every 100 minors apprehended in 2014, Mexico deported 77 of them, compared to three out of 100 for the United States.