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.

Many remain determined to reach the U.S. through more dangerous means, riding freight trains, hiring smugglers and dodging authorities.

The US-Mexico border is effectively closed off to migrants seeking asylum in the United States within hours of President Donald Trump taking office, an extraordinary departure from previous protocols that has left many concerned migrants in limbo.