That’s more children detained away from their parents than any other country, according to United Nations researchers.

``We are burning up our future -- literally,'' Bachelet said. ``The world has never seen a threat to human rights of this scope. This is not a situation where any country, any institution, any policymaker can stand on the sidelines.''

The situation at the U.S.-Mexico border has been called an "invasion," a "national emergency" and a "humanitarian crisis." But what's really happening? 

A sharp drop in illegal border crossings, coming during a seasonal decline as summer heat sets in, has eased pressure temporarily.

U.S. Customs and Border Protection officials said Monday that 62 current and eight former Border Patrol employees are under internal investigation following revelations of a secret Facebook group that mocked lawmakers and migrants.

On Friday, Pence toured two Texas migrant detention centres, one in Donna, the other in McAllen.

Democrats accuse Trump of tolerating badly overcrowded and putrid holding facilities in a purposeful effort to discourage future immigrants.

There were 104,344 people encountered in June, down from 144,278 the month before. May saw a record high number of families cross.

The DHS inspector general on Tuesday published photos of migrant-holding centers in Texas' Rio Grande Valley crammed with twice as many people as they were meant to hold.

First-term Democratic Congresswoman Ocasio-Cortez wrote on Twitter after leaving the main border patrol station in El Paso that she had seen women in cells with no water who had been told to drink out of toilets.