For years, Mexico's most closely watched border was its northern one, which generations of Mexican migrants have crossed into the United States.
But the sudden surge of child migrants from Central America has cast scrutiny on the 600-mile border separating Mexico and Guatemala.
While the public is sympathetic to migrants and critical of the United States' hard-line immigration policies, officials are taking steps that once would have been unthinkable.
Mexico has quietly stepped up the pace of deportation of migrants. It announced plans to stop people from boarding freight trains north and will open five new border control stations.
Last year, Mexico deported 89,000 Central Americans. In the fiscal year that ended last September, the United States sent back 106,420 from those countries.
So far this year, Mexico has detained 53 child migrants a day, mostly Central American, double last year's pace. It has deported more than 30,000 Central Americans so far this year.
Francisco Alba, a migration scholar at the Colegio de Mexico in Mexico City, said it is almost impossible to stop the flow, yet Mexico cannot support a large population of refugees.
"It cannot really stop these flows," Alba said.
