These caravans make up only a small portion of the daily migration through Mexico toward the U.S. border. Most of these groups break apart after a few days, with migrants continuing their journey in smaller groups or with their families.

How will Mexican leaders respond if, as expected, Trump pressures them to accept deportees from third countries? 'Mexico is in a really tough spot.'

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.