Updated

The government said Monday it will soon close three emergency shelters it established at U.S. military bases to temporarily house children caught crossing the Mexican border alone. It said fewer children were being caught and other shelters will be adequate.

A shelter in Oklahoma at Fort Sill is expected to close as early as Friday, the Health and Human Services Department said. Shelters in Texas at Joint Base San Antonio-Lackland and in California at Naval Base Ventura County-Port Hueneme will wrap up operations in the next two to eight weeks, agency spokesman Kenneth Wolfe said. About 7,700 children had been housed at the three military bases since shelters there opened in May and early June. They stayed an average of 35 days.

Since Oct. 1 more than 57,000 unaccompanied children, mostly from Honduras, El Salvador and Guatemala, have been caught crossing the Mexican border illegally.

A 2008 law requires that unaccompanied child immigrants from countries that don't border the United States be handed over to the Health and Human Services Department within 72 hours of being apprehended. The children are cared for by the government until they can be reunited with a relative or another sponsor in the United States while they await a deportation hearing in immigration court.

The crush of Central American children caught at the border in recent months has strained resources across the government and prompted President Barack Obama to ask Congress to approve an emergency $3.7 billion spending bill to deal with what he described as a humanitarian crisis. Members of the House of Representatives left town for the August recess without acting on the request.

Last month the Homeland Security Department reported that the number of child immigrants crossing the border alone had started to decline, from as many as 2,000 each week in June to about 500 each week in mid-July. Administration officials said at the time that multiple factors likely contributed to the decline.

The number of people caught crossing the border illegally typically declines during the hottest summer months.

Administration officials have said as many 90,000 child immigrants could cross the border by the end of the budget year in September.

The military base shelters could reopen if the number of young border crossers spikes again in the near future, Wolfe said.