Mexico City — Mexico now deports more Central American migrants than the United States, a dramatic shift since the U.S. asked Mexico for help a year ago with a spike in illegal migration, especially among unaccompanied minors.

Between October and April, Mexico apprehended 92,889 Central Americans. In the same time period, the United States detained 70,226 "other than Mexican" migrants, the vast majority from Guatemala, Honduras and El Salvador.

That was a huge reversal from the same period a year earlier, when the wave of migrants and unaccompanied minors from Central America was building. From October 2013 to April 2014, the United States apprehended 159,103 "other than Mexicans," three times the 49,893 Central Americans detained by Mexico.

The difference is Mexico's new Southern Border Program, an initiative that included sending 5,000 federal police to the border with Guatemala and more border and highway checkpoints. Raids on migrants increased and authorities focused on keeping migrants off the northbound freight train known as "the Beast," on which many have suffered mutilation injuries.

Neither U.S. nor Mexican immigration officials responded to requests for comment on the change last week, though officials in the past have said it is aimed at reducing dangers facing migrants.

"Mexico is doing the dirty work, the very dirty work, for the United States," said Tomas Gonzalez, a Franciscan friar who runs the "72" shelter for migrants in Tenosique, a town in the southern Mexico state of Tabasco.

In the past, Mexican migration officials looked the other way as thousands rafted across the river at the border and then boarded freight trains north. 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.

Mexico has proved the more efficient in deportations, which is already causing concerns among human rights groups about the new tactics.

In most cases, Mexico holds migrants only long enough to verify their nationalities, and quickly bundles them aboard buses to take them back to their home countries. "The time that foreigners are in immigration (detention) centers depends only on the speed with which the authorities of their (home) countries confirm their nationality," Mexico's National Immigration Institute said in an email response to questions from The Associated Press.