WASHINGTON — The Obama administration has quietly abandoned its aggressive monthslong search for emergency shelters across the nation as the number of children illegally crossing the southern border alone continues to drop.

At the same time, three facilities at military bases in Texas, California and Oklahoma set up as shelters are no longer housing children from Central America.

An official with the Department of Health and Human Services, which led the search for shelters, said there’s been a decrease in the number of children apprehended at the border and an increase in the number of children sent to live with families or friends.

“We have begun to see some initial signs of progress along our southwest border,” said Kenneth Wolfe, a spokesman for HHS’ Administration for Children and Families.

The number of unaccompanied children traveling from El Salvador, Guatemala and Honduras, most through the Rio Grande Valley in Texas, surged this year. But officials say the influx slowed this summer likely because of many factors, including the weather, a media campaign urging parents not to send their children to the U.S. and the arrest of some bringing children over the border.

Advocacy groups that work with immigrants cautioned that there is always a dip in the numbers during hot summer months and that they could spike again.

“It’s seasonal,” said Megan McKenna of Kids in Need of Defense, an organization that provides legal services to unaccompanied immigrant children. “We’ll see what happens when it becomes cooler.”

President Obama asked Congress to approve nearly $4 billion to help with the higher numbers of immigrants crossing the border – including more Border Patrol agents, judges and lawyers and more beds at detention centers – but lawmakers left town for their annual summer recess without acting.

Marshall Fitz, director of immigration policy at the left-leaning Center for American Progress, said the administration may have dropped the search for new shelters because it didn’t have the money.

“Obviously this will become an issue if the numbers climb up again, but without the resources they can’t put into place the infrastructure that might be needed in the future,” Fitz said.

The federal government has been housing unaccompanied minors at nearly 100 shelters across the nation, which will continue. For example, a pair of shelters have operated for years in the Miami area. Those standard shelters are significantly less costly than temporary emergency shelters, Wolfe said.

The administration began a frenetic search for more shelters, in many cases thousands of miles from the border, in May. But the facilities were hard to come by in part because the administration failed to consult – or even notify – state and local leaders of potential sites. In many cases, facilities eventually were rejected after an uproar ensued when the public learned about the location.

The decision to abandon the search altogether was made this month after the administration released statistics that showed the number of unaccompanied minors dropped by nearly half in July from the previous two months.

About 5,500 children were apprehended in July, down from more than 10,000 in May and June.