Here's The Heartbreaking Reality For Thousands Of Kids Who Have Entered The US Illegally

A humanitarian crisis is building as thousands of undocumented children pour across the U.S.-Mexico border, often without their parents.

Thousands of unaccompanied children have fled the violence sweeping Central America, according to ABC News, and the numbers keep growing.

"Up to 350 children are picked up along the U.S.-Mexico border every day, three-quarters of them from El Salvador, Guatemala and Honduras," Homeland Security Secretary Jeh Johnson told the House Homeland Security Committee on Tuesday, according to Reuters.

As more children flood the country, immigration officials are finding it difficult to deal with the numbers. Basic living items such as mattresses, showers and portable toilets have had to be shipped to a warehouse holding the children, according to AP.

The journey for many of these children includes months spent in life-threatening conditions aboard trains that snake across Mexico. Sonia Nazario's Pulitzer prize-winning reporting for the Los Angeles Times chronicles the journey these children take, and the dangers of rape, amputation and death that confront the youngsters.

Here's a look at the heartbreaking life these children now live:

Reuters

Scores of immigrants ride atop the trains of Oaxaca, Mexico in hopes of making it to the U.S.

Reuters

If they do make the journey and get picked up, Border Patrol Agents work to process the scores of children they find.

Reuters

Some sleep in holding cells, like this one in Texas.

Reuters

While others are kept in massive warehouses, like this one for immigrants in Nogales, Arizona.

Children in this Texas holding cell sleep without mattresses or pillows.

Some have phones, and a few boys here try to make calls next to adults who are also detained.

Reuters

In a holding cell in Texas, these girls try to be normal - playing as others sleep.

And in Arizona, two other girls watch the World Cup from their holding cell.