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

Officials had insisted for weeks that criminal violence was responsible for the surge of Central American children and families rather than the perception that minors and parents with children would be allowed to stay in the United States.

In a softening of that position, the U.S. government this week began a regional public-relations campaign to fight the widespread belief in Central America that children and families are allowed to stay in the United States if they are caught by the Border Patrol.

That belief has been fueled both by migrant smugglers seeking more clients and by calls home from children and families who have been released by the thousands in recent years, with notices to appear in immigration court.

The administration said Friday that it was opening detention centers to house families, although it did not provide details.

At the same time, Biden met in Guatemala City with President Otto Perez Molina, who asked the United States to start a temporary work program for Guatemalan migrants and grant "temporary protected status" for Guatemalan migrants. Salvadorans and Hondurans can apply for that status, which offers some protections against deportation.

Homicide, extortion, rape and gang recruitment have risen to epidemic levels in Guatemala, Honduras and El Salvador in recent years. The violence is seen as the key factor driving migrants north, with children making up an increasing proportion of the U.S.-bound flow. The 20,000-plus unaccompanied children from Guatemala, Honduras and El Salvador detained at the U.S. border last year was more than double the previous year's figure.

To coincide with Biden's trip, the Obama administration pledged $93 million in new programs to reduce violence in Central America. The funding includes $40 million to reduce gang membership in Guatemala, $25 million to build 77 youth outreach centers in El Salvador and $18.5 million to build 77 youth outreach centers in Honduras.

"We're approaching this issue with a shared recognition that the current situation is not sustainable. It is unacceptable. And we have a shared responsibility to take significant steps to address this issue," Biden said after meeting with Perez Molina.

"But I want to make clear, Mr. President, the United States recognizes that a key part of the solution to this problem is to address the root causes of this immigration in the first place. Especially poverty, insecurity and the lack of the rule of law."

Biden was also meeting with Salvadoran President Salvador Sanchez Ceren and high-ranking ministers from Honduras and Mexico. The vice president's office said Biden spoke by phone with Honduran President Juan Orlando Hernandez while traveling to Guatemala.

Biden scheduled a meeting in the afternoon with migrants' advocates expected to call for easier immigration to the United States. The vice president's visit coincided with the arrival of two flights carrying at least 250 migrants deported from the United States. Guatemala's migration department said it expected two more such flights Friday, bringing the total of Guatemalans deported in 2014 to 27,140.