Maribel’s plight highlights the despair and desperation of many migrants, who flee violence, poverty and, increasingly, drought and the early effects of climate change in Central America.

The report quotes one senior government manager as calling the situation "a ticking time bomb."

If the frontier of the U.S.-Mexico border represents the America that would exclude me, space is the frontier that invites me.

Sister Munoz said she does her best to inform migrants of the risks and realities on the road. She also tries to disabuse shelter dwellers of any erroneous ideas—such as the existence of immigration documents for them—and does not sugarcoat her answers.

Migrant shelters in Mexico, which have long provided a safe place amidst a dangerous and difficult journey, now face increased crackdowns and harassment from tough new policy turns.

The Mass July 8 will mark the sixth anniversary of the pope's visit to the southern Italian island of Lampedusa.