Nidia Montenegro fled violence and poverty at home in Venezuela, survived a kidnapping as she traveled north into Mexico, and made it to the border city of Tijuana on Sunday for a U.S. asylum appointment that would finally reunite her with her son living in New York.

Groups of migrants began to be deported to Mexico on Tuesday night as border shelters and authorities brace themselves for President Donald Trump's promised campaign of mass deportations.

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.