GUATEMALA CITY (AP) — The Obama administration moved Friday to stem a flood of Central American children and families that has overwhelmed the U.S. immigration system, dispatching Vice President Joe Biden to the region to warn against the perils of the trip and announcing that it will start to detain families at the border instead of releasing them on their own recognizance.

After weeks of insistence that criminal violence was responsible for the surge of Central American migrants, the U.S. has begun a regional public-relations campaign to fight the widespread belief in Central America that children and families will be allowed to stay in the U.S. if they are caught by the Border Patrol.