The Obama administration has warned thousands of undocumented children are at risk of deportation following a wave of migration from Central America. More than 47,000 unaccompanied children have been caught at the U.S. border since October fleeing violence and poverty in their home countries. On Tuesday, Homeland Security Secretary Jeh Johnson told lawmakers the United States is preparing additional detention centers to hold undocumented immigrants.

Homeland Security Secretary Jeh Johnson: “We’re creating additional detention space for adults who bring their children, and I’m considering — I want to consider every option for stemming this tide, sir. We’re talking about large numbers of children, without their parents, who have arrived at our border hungry, thirsty, exhausted, scared and vulnerable. How we treat the children, in particular, is a reflection of our laws and our values.”

Most of the children are from El Salvador, Guatemala and Honduras, and many have come on their own.