A U.S. Office of Air and Marine helicopter patrols over the Rio Grande on July 21, 2014 at the U.S.-Mexico border in McAllen, Texas.
Thousands of immigrants, many of them minors from Central America, have crossed illegally into the United States this year, causing an unprecedented humanitarian crisis on the U.S.-Mexico border. Texas Governor Rick Perry announced on Monday that he will send 1,000 National Guard troops to help stem the flow.
Migrant families walking through trees near McAllen, Texas, before they were taken into custody by border patrol agents on July 21.
Border patrol agents chase undocumented immigrants through the countryside near Falfurrias, Texas, on July 22.
A U.S. Customs and Border Protection agent takes a migrant into custody near Falfurrias, Texas on July 22.
Border Patrol agents take a woman and child into custody on July 21 in McAllen, Texas.
White House press secretary Josh Earnest said on Monday that the number of apprehensions of adults traveling with children in the Rio Grande Valley had dropped since June.
A woman awaits transport to a processing center after being detained on July 22 near Falfurrias, Texas.
A Border Patrol agent endures the heat after taking a group of migrants into custody on July 22 near Falfurrias, Texas.
U.S. Customs and Border Protection agents take undocumented immigrants into custody on July 22 near Falfurrias, Texas.
Migrants are transported to a processing center after being detained on July 22 near Falfurrias, Texas.