Thousands of U.S. agents already patrol the border region where billions of dollars have been spent.

Fleeing violence and poverty, immigrants from Central America's Northern Triangle - El Salvador, Guatemala and Honduras - continue to arrive in the U.S. by the thousands. First, they are processed by Border Patrol. Within 72 hours they are handed over to Immigration and Customs Enforcement or the Department of Health. Some are detained but all are put in deportation proceedings. Those who are released to await the outcome of their cases continue their journey in the U.S. Recent changes allow immigrants to avoid risking their lives on the journey north and to instead submit asylum requests from their home countries.

Marco Gutierrez, a Mexican immigrant, told MSNBC Thursday night about what he thinks will happen if the U.S. doesn't do something about undocumented immigration.

Several prominent Latino Republicans expressed their frustration after hearing the Republican candidate's speech in Phoenix Wednesday.

In Arizona Wednesday, the Republican candidate said he would focus on deportations and restricting immigration.

Latin American governments call on the United States to end special treatment for Cuban migrants.