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.

When Dayana Castro heard that the U.S. asylum appointment she waited over a year for was canceled in an instant, she had no doubt: She was heading north any way she could. The 25-year-old migrant, her husband and their 4- and 7-year-old children had nothing left at home in Venezuela.

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.