How is this one different?
For years an annual caravan was organized by advocacy groups in southern Mexico around Easter to draw attention to the plight of Central American migrants.
But since Trump took office in 2017, the caravans have grabbed attention in the United States and grown from only a few hundred to more than 1,000 people.
Earlier this year, a smaller caravan made its way to Tijuana, where more than 200 people presented themselves at the border and applied for asylum in the United States. The others returned home, tried to sneak into the United States or were deported by the U.S. or Mexico.
With just two weeks before the Nov. 6 midterm elections in the U.S., Trump has seized on the migrant caravan to make border security a political issue and energize his Republican base.
Trump has accused Democrats of failing on border policy and said the United States will “begin cutting off” foreign aid to Guatemala, Honduras and El Salvador for not stopping their people from migrating. He said he is also considering using the U.S. military to seal off the border.
As Trump has tweeted his criticisms, the caravan has continued to grow.