"Our message absolutely is don't send your children unaccompanied, on trains or through a bunch of smugglers," Obama told ABC News on Thursday in an interview. "We don't even know how many of these kids don't make it, and may have been waylaid into sex trafficking or killed because they fell off a train."
"Do not send your children to the borders," Obama said. "If they do make it, they'll get sent back. More importantly, they may not make it."
Republicans in Congress, who blame the influx of minors on a drop in deportations, have called in recent days for Obama to make such a public warning.
The president called the surge of young immigrants at the border a "humanitarian crisis."
The administration says an estimated 52,000 unaccompanied minors have been detained since October, driven from their homes by violence and false rumors that they'll be allowed to stay.
The situation is threatening to become a political liability for the president and has his advisors rethinking plans to take executive action to ease deportation policies this fall.