Homeland Security Sec. John Kelly confirmed today that he is considering separating the children of undocumented immigrants from their parents if they are apprehended while illegally crossing the border.

“Yes, I am considering, in order to deter more movement along this terribly dangerous network, I am considering exactly that,” Kelly told CNN host Wolf Blitzer. “They will be well cared for as we deal with their parents.”

Kelly said he thought the change might deter mothers and children from making the dangerous journey from Guatemala, Honduras, and El Salvador to the United States.

“You understand how that looks to the average person who is, you know…” Blitzer replied.

“It’s more important to me, Wolf, to try to keep people off of this awful network,” Kelly said.

Currently, mothers and children who cross the border together—and it’s virtually always mothers and children, rather than fathers—stay together. In many cases, they’re put in family detention centers, though they are frequently released quickly while they await asylum hearings. Reuters reported on March 4 that the Department of Homeland Security was considering separating mothers from their children when it apprehended them. Mothers would be put in detention centers, while their children would be in the custody of the Department of Health and Human Services, according to the report.

The smuggling networks Kelly referenced move people from incredibly violent Central American countries to the United States often exploit them along the way, and women are frequently sexually assaulted on the journey. In many cases, migrants take great risks because they fear death in their home countries—as was the case for Sara Beltran Hernandez, an undocumented woman from El Salvador who entered the U.S. in November of 2015 and was recently released from ICE detention to get better medical care for a brain tumor.

Kelly’s confirmation that he is considering separating children from their parents shocked children’s advocates.

“It’s unbelievable,” said Matthew Kolken, an immigration attorney from Buffalo, N.Y. who frequently represents undocumented children.

“He’s going to be traumatizing young children even more than they are by pulling them from their mother’s arms,” he said.

“Who knows what they’re going to do with them?” he added.