In Mexico City, some migrants have built tent cities and slept on the streets. In a country long sympathetic to migrants, neighbors are protesting.

A sense of despair has engulfed the migrant camp of La Soledad, named after the colonial-era church that towers over the shantytown in downtown Mexico City. It was supposed to be a temporary stop, a place to regroup and wait for the right moment to continue on toward the United States.

Naser Zazai, 29, had planned to reunite with his mother and brother in the United States this week after fleeing Afghanistan, where he says he was threatened and attacked because his brother had once worked for the U.